Ab initio spectroscopic characterization of the radical CH3_3OCH2_2 at low temperatures

Spectroscopic and structural properties of methoxymethyl radical (CH$_3$OCH$_2$, RDME) are determined using explicitly correlated ab initio methods. This radical of astrophysical and atmospheric relevance has not been fully characterized at low temperatures, which has delayed the astrophysical searches. We provide rovibrational parameters, excitations to the low energy electronic states, torsional and inversion barriers and low vibrational energy levels. In the electronic ground state (X$^2$A), which appears "clean" from non-adiabatic effects, the minimum energy structure is an asymmetric geometry which rotational constants and dipole moment have been determined to be A$_0$=46718.6745 MHz, B$_0$=10748.4182 MHz, and C$_0$=9272.5105 MHz, and 1.432 D ($\mu_A$=0.6952 D, $\mu_B$=1.215 D, $\mu_C$=0.3016 D), respectively. A variational procedure has been applied to determine torsion-inversion energy levels. Each level splits into 3 subcomponents (A$_1$/A$_2$ and E) corresponding to the three methyl torsion minima. Although the potential energy surface presents 12 minima, at low temperatures, the infrared band shapes correspond to a surface with only three minima because the top of the inversion V$^{\alpha}$ barrier at ${\alpha}=0^{\circ}$ (109 cm$^{-1}$) stands below the zero point vibrational energy and the CH$_2$ torsional barrier is relatively high ($\sim$2000 cm$^{-1}$). The methyl torsion barrier was computed to be $\sim$500 cm$^{-1}$ and produces a splitting of 0.01 cm$^{-1}$ of the ground vibrational state

Understanding of matrix embedding: a theoretical spectroscopic study of CO interacting with Ar clusters, surfaces and matrices

Through benchmark studies, we explore the performance of PBE density functional theory, with and without Grimme's dispersion correction (DFT-D3), in predicting spectroscopic properties for molecules interacting with rare gas matrices. Here, a periodic-dispersion corrected model of matrix embedding is used for the first time. We use PBE-D3 to determine the equilibrium structures and harmonic vibrational frequencies of carbon monoxide in interaction with small Ar clusters (CO–Arn, n = 1, 2, 3), with an Ar surface and embedded in an Ar matrix. Our results show a converging trend for both the vibrational frequencies and binding energies when going from the gas-phase to a fully periodic approach describing CO embedding in Ar. This trend is explained in terms of solvation effects, as CO is expected to alter the structure of the Ar matrix. Due to a competition between CO–Ar interactions and Ar–Ar interactions, perturbations caused by the presence of CO are found to extend over several Å in the matrix. Accordingly, it is mandatory to fully relax rare gas matrices when studying their interaction with embedded molecules. Moreover, we show that the binding energy per Ar is almost constant (∼−130 cm−1 atom−1) regardless of the environment of the CO molecule. Finally, we show that the concentration of the solute into the cold matrix influences the spectroscopic parameters of molecules embedded into cold matrices. We suggest hence that several cautions should be taken before comparing these parameters to gas phase measurements and to theoretical data of isolated species

Time and space exchanging greetings. Sketches towards an understanding of utmark production landscapes in a cognitive perspective

publishedVersio

Adaptive Dynamics of Realistic Small-World Networks

Continuing in the steps of Jon Kleinberg's and others celebrated work on decentralized search in small-world networks, we conduct an experimental analysis of a dynamic algorithm that produces small-world networks. We find that the algorithm adapts robustly to a wide variety of situations in realistic geographic networks with synthetic test data and with real world data, even when vertices are uneven and non-homogeneously distributed. We investigate the same algorithm in the case where some vertices are more popular destinations for searches than others, for example obeying power-laws. We find that the algorithm adapts and adjusts the networks according to the distributions, leading to improved performance. The ability of the dynamic process to adapt and create small worlds in such diverse settings suggests a possible mechanism by which such networks appear in nature

A New Takings Clause? The Implications of Cedar Point Nursery v. Hassid for Property Rights and Moratoria

In part, the Fifth Amendment to the Constitution holds that “no person . . . shall [have their] private property . . . taken for public use, without just compensation.” In Cedar Point Nursery v. Hassid, the U.S. Supreme Court ruled that “a California regulation that permits union organizers to enter the property of agricultural business to talk with employees about supporting a union is unconstitutional.” The purpose of this Note is to discuss what Cedar Point Nursery means generally for the future of Takings Clause analysis and will argue that Cedar Point Nursery should be seen as a seminal case that will alter the Court’s Takings Clause analysis as it is currently understood. Additionally, this Note will use the recent eviction moratorium as a case study, predicting the success of landlords at recovering income under the Takings Clause. Part I of this Note will focus on the history of the Takings Clause, the relationship of the Takings Clause to property rights in the Western tradition, a generalized history of property rights in the Western tradition, and the role of the Takings Clause as a limitation on private property rights in the United States. Part II of this Note will provide an overview of takings pre–Cedar Point, focusing on the different kinds of takings, the use of history by the Supreme Court to decide Takings Clause cases, and the meaning of “just compensation.” Part III of this Note will provide an overview of expected Takings Clause analysis after Cedar Point Nursery, addressing the future of temporary takings and per se takings by analyzing the opinion of the Court in Cedar Point Nursery. Part III will also address Justice Breyer’s dissent in Cedar Point Nursery. Part IV will address a normative question: whether the Supreme Court made the right decision in Cedar Point Nursery, highlighting both an Originalist and a non-Originalist argument as well as other arguments that could be made regarding the Court’s decision. Finally, Part V will address the expectation for landlords making a Takings Clause claim given the Court’s Takings Clause jurisprudence in Cedar Point Nursery. This abstract has been adapted from the author\u27s introduction

Physical activity and persistent low back pain and pelvic pain post partum

<p>Abstract</p> <p>Background</p> <p>The aims of this study were (i) to investigate the potential influence of pre-pregnancy regular leisure-time physical activity (PA) on the risk of persistent LBPP half a year after pregnancy, and (ii) to explore the starting time and prevalence of PA among women experiencing LBPP during pregnancy, in relation to remission or persistent LBPP half a year after pregnancy.</p> <p>Methods</p> <p>This study is a follow-up study of 639 women who reported LBPP during pregnancy. These women were sent a questionnaire at approximately six months after delivery. The respondents were divided into three groups: 'no pain', 'recurrent pain', and 'continuous pain'. Data were analysed using an independent samples t-test, Pearson's chi-squared test, and univariate and multivariate logistic regression analyses.</p> <p>Results</p> <p>44.5% of subjects reported current PA at six months post partum. The mean starting time of PA was 2.6 months post partum and the mean number of current, weekly events of PA was 3.4; there were no differences between the groups. 82.2% reported previous PA at some period in life. Women with BMI ≥ 30 reported current PA to a lesser extent. The number of years of pre-pregnancy PA did not influence the risk of persistent LBPP.</p> <p>Conclusion</p> <p>Almost half of women who had experienced LBPP during pregnancy reported PA at six months post partum. The number of years of pre-pregnancy PA did not influence the risk of persistent LBPP. Obesity was a risk factor for not practising PA.</p

Height growth in relation to crown size in juvenile lodgepole pine

October, 1967

Trophic Transfer of Arsenic from an Aquatic Insect to Terrestrial Insect Predators.

The movement of energy and nutrients from aquatic to terrestrial ecosystems can be substantial, and emergent aquatic insects can serve as biovectors not only for nutrients, but also for contaminants present in the aquatic environment. The terrestrial predators Tenodera aridifolia sinensis (Mantodea: Mantidae) and Tidarren haemorrhoidale (Araneae: Theridiidae) and the aquatic predator Buenoa scimitra (Hemiptera: Notonectidae) were chosen to evaluate the efficacy of arsenic transfer between aquatic and terrestrial environments. Culex tarsalis larvae were reared in either control water or water containing 1000 µg l(-1) arsenic. Adults that emerged from the control and arsenic treatments were fed to the terrestrial predators, and fourth instar larvae were fed to the aquatic predator reared in control or arsenic contaminated water. Tenodera a. sinensis fed arsenic-treated Cx. tarsalis accumulated 658±130 ng g(-1) of arsenic. There was no significant difference between control and arsenic-fed T. haemorrhoidale (range 142-290 ng g(-1)). Buenoa scimitra accumulated 5120±406 ng g(-1) of arsenic when exposed to arsenic-fed Cx. tarsalis and reared in water containing 1000 µg l(-1) arsenic. There was no significant difference between controls or arsenic-fed B. scimitra that were not exposed to water-borne arsenic, indicating that for this species environmental exposure was more important in accumulation than strictly dietary arsenic. These results indicate that transfer to terrestrial predators may play an important role in arsenic cycling, which would be particularly true during periods of mass emergence of potential insect biovectors. Trophic transfer within the aquatic environment may still occur with secondary predation, or in predators with different feeding strategies

A Powerful Optimization Approach for the Multi Channel Dissemination Networks

In the wireless environment, dissemination techniques may improve data access for the users. In this paper, we show a description of dissemination architecture that fits the overall telecommunication network. This architecture is designed to provide efficient data access and power saving for the mobile units. A concurrency control approach, MCD, is suggested for data consistency and conflict checking. A performance study shows that the power consumption, space overhead, and response time associated with MCD is far less than other previous techniques.Comment: 9 Pages, IJCNC Journal 201