The 3-state Potts model as a heavy quark finite density laboratory

The 3-D Z(3) Potts model is a model for finite temperature QCD with heavy quarks. The chemical potential in QCD becomes an external magnetic field in the Potts model. Following Alford et al.\cite{Alford_et_al}, we revisit this mapping, and determine the phase diagram for an arbitrary chemical potential, real or imaginary. Analytic continuation of the phase transition line between real and imaginary chemical potential can be tested with precision. Our results show that the chemical potential weakens the heavy-quark deconfinement transition in QCD.Comment: 6 pages and 7 figures. talk presented at Lattice 2005 (non-zero temperature and density

Symmetric Versus Nonsymmetric Structure of the Phosphorus Vacancy on InP(110)

The atomic and electronic structure of positively charged P vacancies on InP(110) surfaces is determined by combining scanning tunneling microscopy, photoelectron spectroscopy, and density-functional theory calculations. The vacancy exhibits a nonsymmetric rebonded atomic configuration with a charge transfer level 0.75+-0.1 eV above the valence band maximum. The scanning tunneling microscopy (STM) images show only a time average of two degenerate geometries, due to a thermal flip motion between the mirror configurations. This leads to an apparently symmetric STM image, although the ground state atomic structure is nonsymmetric.Comment: 5 pages including 3 figures. related publications can be found at http://www.fhi-berlin.mpg.de/th/paper.htm

Stochastic Language Generation in Dialogue using Recurrent Neural Networks with Convolutional Sentence Reranking

The natural language generation (NLG) component of a spoken dialogue system (SDS) usually needs a substantial amount of handcrafting or a well-labeled dataset to be trained on. These limitations add significantly to development costs and make cross-domain, multi-lingual dialogue systems intractable. Moreover, human languages are context-aware. The most natural response should be directly learned from data rather than depending on predefined syntaxes or rules. This paper presents a statistical language generator based on a joint recurrent and convolutional neural network structure which can be trained on dialogue act-utterance pairs without any semantic alignments or predefined grammar trees. Objective metrics suggest that this new model outperforms previous methods under the same experimental conditions. Results of an evaluation by human judges indicate that it produces not only high quality but linguistically varied utterances which are preferred compared to n-gram and rule-based systems.Comment: To be appear in SigDial 201

Evaluating the impact of a sport-based corporate social responsibility program on multicultural youth in South Korea

textWith increasing attention being given to corporate social responsibility (CSR) by corporations, it has become apparent that more corporations are involved in CSR initiatives. Sport business entities also have widely embraced the principles and practices of CSR over the past decades (Babiak & Wolfe, 2009; Bradish & Cronin, 2009). The deployment of CSR through sport offers substantial potential for a return to the community due to the ubiquitous appeal of sport, so that CSR in sport has been practiced by a considerable number of athletes, teams, leagues, sport franchises, and sporting goods manufacturing companies (Bardish & Cronin, 2009). Despite the increasing emphasis on CSR initiatives using sport in the marketplace, little is known about the effects of CSR programs. In other words, there is little transparent evidence that demonstrates the effectiveness of CSR programs in sport. Hence, the purpose of this study is to determine if a sport-based corporate social responsibility program provides discernable benefits to its participants. It also seeks to determine if the program meets the needs of the intended beneficiaries. Furthermore, it tries to see if the CSR program through sport is not misused as a PR strategy or a device to please shareholders. Through a series of interviews with program stakeholders, secondary document analysis, and personal observations, the researcher was able to assess the outcomes of a baseball program for multicultural children in Korea, operated by a nonprofit baseball foundation. The findings of this study have shown that the program did produce a positive change in the attitudes and opinions of the participants. However, the findings of this study also showed that some promises that the foundation made were not fulfilled. Beneath the surface of the public-facing socially responsible program was a somewhat devious plan by the foundation to exploit the children for bolstering the foundation’s public image. The founder did just enough to ensure his foundation was viewed as socially responsible but not enough to operate a good quality program.Kinesiology and Health Educatio

Towards a controlled study of the QCD critical point

The phase diagram of QCD, as a function of temperature T and quark chemical potential mu, may contain a critical point (mu_E,T_E) whose non-perturbative nature makes it a natural object of lattice studies. However, the sign problem prevents the application of standard Monte Carlo techniques at non-zero baryon density. We have been pursuing an approach free of the sign problem, where the chemical potential is taken as imaginary and the results are Taylor-expanded in mu/T about mu=0, then analytically continued to real mu. Within this approach we have determined the sensitivity of the critical chemical potential mu_E to the quark mass, d(\mu_E)^2/dm_q|_{\mu_E=0}. Our study indicates that the critical point moves to {\em smaller} chemical potential as the quark mass {\em increases}. This finding, contrary to common wisdom, implies that the deconfinement crossover, which takes place in QCD at mu=0 when the temperature is raised, will remain a crossover in the mu-region where our Taylor expansion can be trusted. If this result, obtained on a coarse lattice, is confirmed by simulations on finer lattices now in progress, then we predict that no {\em chiral} critical point will be found for mu_B \lesssim 500 MeV, unless the phase diagram contains additional transitions.Comment: 4 pages, 6 figures, proceedings of Quark Matter 2008, Jaipur (India), Feb. 2008, to appear in J. Phys.

Four-probe thermal and thermoelectric transport measurements of bismuth antimony telluride, silicon, and boron arsenide nanostructures

Thermal management in electronic devices has become a significant challenge because of the high power density in nanoelectronic devices. This challenge calls for a better understanding of thermal transport processes in nanostructures and devices, as well as new thermal management approaches such as high thermal conductivity materials and efficient on-chip thermoelectric coolers. While several experimental methods have been developed to investigate size-dependent thermal and thermoelectric properties, there are a number of limitations in the current experimental capability in probing nanoscale thermal and thermoelectric transport properties. Among these limitations is the difficulty in determining and eliminating the contact thermal resistance error so as to obtain the intrinsic thermal and thermoelectric properties of nanostructures. This dissertation presents an effort to develop new experimental methods for uncovering the intrinsic thermal and thermoelectric properties of nanostructures, and the applications of these methods for investigating the thermal and thermoelectric transport phenomena in three materials systems. The intrinsic thermoelectric properties of bismuth antimony telluride nanostructures, which are synthesized by two different methods, are characterized with a four-probe thermoelectric measurement method based on a suspended device. The obtained thermoelectric property reveals a transition from n-type to p-type electronic transport as the antimony to bismuth ratio is increased to about 0.25. The peak zT was found when this ratio is close to 0.5. A new four-probe thermal transport measurement method is established in this work to probe both the contact thermal resistance and intrinsic thermal resistance of a nanostructure, which can be either an electrical conductor or insulator. The effectiveness of this method is demonstrated with its use to reveal size-dependent thermal conductivity of patterned silicon nanowires. The new four-probe measurement method is employed to obtain both the intrinsic thermal and thermoelectric properties of nanostructures of boron arsenide (BAs) with potentially record high thermal conductivity. The measurement results suggest that the thermal conductivity of one of such sample with an equivalent diameter of about 1.1 μm is higher than that of bulk silicon, despite pronounced phonon scattering by surface roughness and point defects associated with arsenic vacancies. In addition, high thermoelectric power factor was measured on the BAs sample.Mechanical Engineerin

Making Linux protection mechanisms egalitarian with UserFS

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 46-51).UserFS provides egalitarian OS protection mechanisms in Linux. UserFS allows any user-not just the system administrator-to allocate Unix user IDs, to use chroot, and to set up firewall rules in order to confine untrusted code. One key idea in UserFS is representing user IDs as files in a /proc-like file system, thus allowing applications to manage user IDs like any other files, by setting permissions and passing file descriptors over Unix domain sockets. UserFS addresses several challenges in making user IDs egalitarian, including accountability, resource allocation, persistence, and UID reuse. We have ported several applications to take advantage of UserFS; by changing just tens to hundreds of lines of code, we prevented attackers from exploiting application-level vulnerabilities, such as code injection or missing ACL checks in a PHP-based wiki application. Implementing UserFS requires minimal changes to the Linux kernel-a single 3,000-line kernel module-and incurs no performance overhead for most operations, making it practical to deploy on real systems.by Taesoo Kim.S.M

Telemedicine and Telementoring in Rhinology, Otology, and Laryngology: A Scoping Review

Objective: Telemedicine and telementoring have had a significant boost across all medical and surgical specialties over the last decade and especially during the COVID-19 pandemic. The aim of this scoping review is to synthesize the current use of telemedicine and telementoring in otorhinolaryngology and head and neck surgery. Data Sources: PubMed and Cochrane Library. Review Methods: A scoping review search was conducted, which identified 469 articles. Following full-text screening by 2 researchers, 173 articles were eligible for inclusion and further categorized via relevant subdomains. Conclusions: Virtual encounters and telementoring are the 2 main applications of telemedicine in otolaryngology. These applications can be classified into 7 subdomains. Different ear, nose, and throat subspecialties utilized certain telemedicine applications more than others; for example, almost all articles on patient engagement tools are rhinology based. Overall, telemedicine is feasible, showing similar concordance when compared with traditional methods; it is also cost-effective, with high patient and provider satisfaction. Implications for Practice: Telemedicine in otorhinolaryngology has been widely employed during the COVID-19 pandemic and has a huge potential, especially with regard to its distributing quality care to rural areas. However, it is important to note that with current exponential use, it is equally crucial to ensure security and privacy and integrate HIPAA-compliant systems (Health Insurance Portability and Accountability Act) in the big data era. It is expected that many more applications developed during the pandemic are here to stay and will be refined in years to come

Multiorbital tunneling ionization of the CO molecule

We coincidently measure the molecular frame photoelectron angular distribution and the ion sum-momentum distribution of single and double ionization of CO molecules by using circularly and elliptically polarized femtosecond laser pulses, respectively. The orientation dependent ionization rates for various kinetic energy releases allow us to individually identify the ionizations of multiple orbitals, ranging from the highest occupied to the next two lower-lying molecular orbitals for various channels observed in our experiments. Not only the emission of a single electron, but also the sequential tunneling dynamics of two electrons from multiple orbitals are traced step by step. Our results confirm that the shape of the ionizing orbitals determine the strong laser field tunneling ionization in the CO molecule, whereas the linear Stark effect plays a minor role.Comment: This paper has been accepted for publication by Physical Review Letter