Reassessment of the classical closures for scalar turbulence

In deducing the consequences of the Direct Interaction Approximation, Kraichnan was sometimes led to consider the properties of special classes of nonlinear interactions in degenerate triads in which one wavevector is very small. Such interactions can be described by simplified models closely related to elementary closures for homogeneous isotropic turbulence such as the Heisenberg and Leith models. These connections can be exploited to derive considerably improved versions of the Heisenberg and Leith models that are only slightly more complicated analytically. This paper applies this approach to derive some new simplified closure models for passive scalar advection and investigates the consistency of these models with fundamental properties of scalar turbulence. Whereas some properties, such as the existence of the Kolmogorov–Obukhov range and the existence of thermal equilibrium ensembles, follow the velocity case closely, phenomena special to the scalar case arise when the diffusive and viscous effects become important at different scales of motion. These include the Batchelor and Batchelor– Howells–Townsend ranges pertaining, respectively, to high and low molecular Schmidt number. We also consider the spectrum in the diffusive range that follows the Batchelor range. We conclude that improved elementary models can be made consistent with many nontrivial properties of scalar turbulence, but that such models have unavoidable limitations

Small Cells, Big Problems: The Increasing Precision of Cell Site Location Information and the Need for Fourth Amendment Protections

The past fifty years has witnessed an evolution in technology advancement in police surveillance. Today, one of the essential tools of police surveillance is something most Americans carry with them in their pockets every day, the cell phone. Cell phones not only contain a huge repository of personal data, they also provide continuous surveillance of a person’s movement known as cell site location information (CSLI). In 1986, Congress sought to provide some privacy protections to CSLI in the Stored Communication Act. Although this solution may have struck the proper balance in an age when cell phones were a mere novelty in the hands of a comparative few, we now live in an age where, as the U.S. Supreme Court recently recognized, cell phones could be seen “an important feature of human anatomy.” In 1986, there were only an estimated 681,825 subscribers serviced by 1531, cell sites. By 2013, there were 335 million subscribers and over 340,000 cell sites. Recently, cell phone service providers have begun to use small cell technologies, miniature cell phone towers that can provide additional coverage and bandwidth support to overburdened cellular networks. Small cells, known variously as femtocells, picocells, and microcells, are already installed throughout the United States, in particular in urban areas. As small cells overtake traditional cell phone towers as the most common means of transmitting cellular signals, CSLI will transform from a means of placing a person’s phone in a general area within a matter of miles to a precise location tracking tool charting a person’s movements down to a matter of feet. The late Justice Scalia in his 2001 majority opinion in Kyllo v. U.S., a case involving thermal imaging, opined that “while the technology used in the present case was relatively crude, the rule we adopt must take account of more sophisticated systems that are already in use or in development.” This Article explores the evolution of CSLI by focusing on the rise of small cell technologies. It also canvasses decisions in the circuits involving CSLI. It points out that the third-party exception to the Fourth Amendment is inapplicable to CSLI. Following Justice Scalia’s admonition, we believe that CSLI will only grow more precise as small cells infiltrate cellular networks and we therefore adopt an approach that incorporates the Fourth Amendment requirements for a search warrant particularly describing the place to be searched and items to be seized as well as the requirement for probable cause. Placing CSLI under the Fourth Amendment would make a major section of the Stored Communication Act unconstitutional

Small Scale Response and Modeling of Periodically Forced Turbulence

The response of the small scales of isotropic turbulence to periodic large scale forcing is studied using two-point closures. The frequency response of the turbulent kinetic energy and dissipation rate, and the phase shifts between production, energy and dissipation are determined as functions of Reynolds number. It is observed that the amplitude and phase of the dissipation exhibit nontrivial frequency and Reynolds number dependence that reveals a filtering effect of the energy cascade. Perturbation analysis is applied to understand this behavior which is shown to depend on distant interactions between widely separated scales of motion. Finally, the extent to which finite dimensional models (standard two-equation models and various generalizations) can reproduce the observed behavior is discussed

(Per)chlorate-reducing bacteria can utilize aerobic and anaerobic pathways of aromatic degradation with (per)chlorate as an electron acceptor.

UnlabelledThe pathways involved in aromatic compound oxidation under perchlorate and chlorate [collectively known as (per)chlorate]-reducing conditions are poorly understood. Previous studies suggest that these are oxygenase-dependent pathways involving O2 biogenically produced during (per)chlorate respiration. Recently, we described Sedimenticola selenatireducens CUZ and Dechloromarinus chlorophilus NSS, which oxidized phenylacetate and benzoate, two key intermediates in aromatic compound catabolism, coupled to the reduction of perchlorate or chlorate, respectively, and nitrate. While strain CUZ also oxidized benzoate and phenylacetate with oxygen as an electron acceptor, strain NSS oxidized only the latter, even at a very low oxygen concentration (1%, vol/vol). Strains CUZ and NSS contain similar genes for both the anaerobic and aerobic-hybrid pathways of benzoate and phenylacetate degradation; however, the key genes (paaABCD) encoding the epoxidase of the aerobic-hybrid phenylacetate pathway were not found in either genome. By using transcriptomics and proteomics, as well as by monitoring metabolic intermediates, we investigated the utilization of the anaerobic and aerobic-hybrid pathways on different electron acceptors. For strain CUZ, the results indicated utilization of the anaerobic pathways with perchlorate and nitrate as electron acceptors and of the aerobic-hybrid pathways in the presence of oxygen. In contrast, proteomic results suggest that strain NSS may use a combination of the anaerobic and aerobic-hybrid pathways when growing on phenylacetate with chlorate. Though microbial (per)chlorate reduction produces molecular oxygen through the dismutation of chlorite (ClO2(-)), this study demonstrates that anaerobic pathways for the degradation of aromatics can still be utilized by these novel organisms.ImportanceS. selenatireducens CUZ and D. chlorophilus NSS are (per)chlorate- and chlorate-reducing bacteria, respectively, whose genomes encode both anaerobic and aerobic-hybrid pathways for the degradation of phenylacetate and benzoate. Previous studies have shown that (per)chlorate-reducing bacteria and chlorate-reducing bacteria (CRB) can use aerobic pathways to oxidize aromatic compounds in otherwise anoxic environments by capturing the oxygen produced from chlorite dismutation. In contrast, we demonstrate that S. selenatireducens CUZ is the first perchlorate reducer known to utilize anaerobic aromatic degradation pathways with perchlorate as an electron acceptor and that it does so in preference over the aerobic-hybrid pathways, regardless of any oxygen produced from chlorite dismutation. D. chlorophilus NSS, on the other hand, may be carrying out anaerobic and aerobic-hybrid processes simultaneously. Concurrent use of anaerobic and aerobic pathways has not been previously reported for other CRB or any microorganisms that encode similar pathways of phenylacetate or benzoate degradation and may be advantageous in low-oxygen environments

Rural Teachers in Project Launch

The success of Project Launch, a teacher induction program sponsored by a regional teacher center and a consortium of universities, is compared for rural and non-rural participants. Indicators of success include teacher accomplishment of action plan goals, teacher self and mentor assessment of teaching strengths related to action plan goals, profiles of teaching strengths, and retention in teaching. Measures of teaching strength are related to INTASC standards. Rural participants differed significantly from non-rural participants in their lower self-perceived accomplishment of action plan goals. Rural participants were significantly more likely to move from their 1st positions after 1 year, but their attrition was not significantly different in later years. Ways to structure induction programs more effectively for rural participants are proposed

In-situ measurements of the optical absorption of dioxythiophene-based conjugated polymers

Conjugated polymers can be reversibly doped by electrochemical means. This doping introduces new sub-bandgap optical absorption bands in the polymer while decreasing the bandgap absorption. To study this behavior, we have prepared an electrochemical cell allowing measurements of the optical properties of the polymer. The cell consists of a thin polymer film deposited on gold-coated Mylar behind which is another polymer that serves as a counterelectrode. An infrared transparent window protects the upper polymer from ambient air. By adding a gel electrolyte and making electrical connections to the polymer-on-gold films, one may study electrochromism in a wide spectral range. As the cell voltage (the potential difference between the two electrodes) changes, the doping level of the conjugated polymer films is changed reversibly. Our experiments address electrochromism in poly(3,4-ethylene-dioxy-thiophene) (PEDOT) and poly(3,4-dimethyl-propylene-dioxy-thiophene) (PProDOT-Me$_2$). This closed electrochemical cell allows the study of the doping induced sub-bandgap features (polaronic and bipolaronic modes) in these easily oxidized and highly redox switchable polymers. We also study the changes in cell spectra as a function of polymer thickness and investigate strategies to obtain cleaner spectra, minimizing the contributions of water and gel electrolyte features

Strategic toolkits: seniority, usage and performance in the German SME machinery and equipment sector

This paper examines the strategic tool kit, from a human resource management (HRM) perspective, in terms of usage and impact. Research to date has tended to consider usage, assuming to a certain extent that knowledge and understanding of particular tools suggest that practitioners value them. The research on which this paper is based builds upon the idea that usage indicates satisfaction, but develops the usage theme to investigate which decision-makers are actually engaged in both tool appliance and the strategic process. Of particular interest to the researchers are the educational background, age and seniority of the decision-makers. In addition, potential links with HRM and organizational performance are also explored. The context of the research, the German machinery and equipment sector, provides an insight into the industry's ability to sustain growth in face of increasing international competition. The paper calls for a greater awareness, from a human resource perspective, and utilization of strategic management practice and associated decision-making aids

Bedrock Geology of the St. Ansgar 7.5\u27 Quadrangle, Mitchell County, Iowa

https://ir.uiowa.edu/igs_ofm/1113/thumbnail.jp

Bedrock Geology of the Mason City 7.5\u27 Quadrangle, Cerro Gordo County, Iowa

https://ir.uiowa.edu/igs_ofm/1109/thumbnail.jp