Exact parameterization of fermionic wave functions via unitary coupled cluster theory

A formal analysis is conducted on the exactness of various forms of unitary coupled cluster (UCC) theory based on particle-hole excitation and de-excitation operators. Both the conventional single exponential UCC parameterization and a factorized (referred to here as “disentangled”) version are considered. We formulate a differential cluster analysis to determine the UCC amplitudes corresponding to a general quantum state. The exactness of conventional UCC (ability to represent any state) is explored numerically, and it is formally shown to be determined by the structure of the critical points of the UCC exponential mapping. A family of disentangled UCC wave functions is proven to exactly parameterize any state, thus showing how to construct Trotter-error-free parameterizations of UCC for applications in quantum computing. From these results, we construct an exact disentangled UCC parameterization that employs an infinite sequence of particle-hole or general one- and two-body substitution operators

Exact parameterization of fermionic wave functions via unitary coupled cluster theory

A formal analysis is conducted on the exactness of various forms of unitary coupled cluster (UCC) theory based on particle-hole excitation and de-excitation operators. Both the conventional single exponential UCC parameterization and a factorized (referred to here as “disentangled”) version are considered. We formulate a differential cluster analysis to determine the UCC amplitudes corresponding to a general quantum state. The exactness of conventional UCC (ability to represent any state) is explored numerically, and it is formally shown to be determined by the structure of the critical points of the UCC exponential mapping. A family of disentangled UCC wave functions is proven to exactly parameterize any state, thus showing how to construct Trotter-error-free parameterizations of UCC for applications in quantum computing. From these results, we construct an exact disentangled UCC parameterization that employs an infinite sequence of particle-hole or general one- and two-body substitution operators

Modeling the Formation of Secondary Organic Aerosol. 1. Application of Theoretical Principles to Measurements Obtained in the α-Pinene/, β-Pinene/, Sabinene/, Δ^3-Carene/, and Cyclohexene/Ozone Systems

Secondary organic aerosol (SOA) forms in the atmosphere when volatile parent compounds are oxidized to form low-volatility products that condense to yield organic particulate matter (PM). Under conditions of intense photochemical smog, from 40 to 80% of the particulate organic carbon can be secondary in origin. Because describing multicomponent condensation requires a compound-by-compound identification and quantification of the condensable compounds, the complexity of ambient SOA has made it difficult to test the ability of existing gas/particle (G/P) partitioning theory to predict SOA formation in urban air. This paper examines that ability using G/P data from past laboratory chamber experiments carried out with five parent hydrocarbons (HCs) (four monoterpenes at 308 K and cyclohexene at 298 K) in which significant fractions (61−100%) of the total mass of SOA formed from those HCs were identified and quantified by compound. The model calculations were based on a matrix representation of the multicomponent, SOA G/P distribution process. The governing equations were solved by an iterative method. Input data for the model included (i) ΔHC (μg m^(-3)), the amount of reacted parent hydrocarbon; (ii) the α values that give the total concentration T (gas + particle phase, ng m^(-3)) values for each product i according to Ti = 10^3 αiΔHC; (iii) estimates of the pure compound liquid vapor pressure P^o_L values (at the reaction temperature) for the products; and (iv) UNIFAC parameters for estimating activity coefficients in the SOA phase for the products as a function of SOA composition. The model predicts the total amount M_o (μg m^(-3)) of organic aerosol that will form from the reaction of ΔHC, the total aerosol yield Y (= M_o/ΔHC), and the compound-by-compound yield values Y_i. An impediment in applying the model is the lack of literature data on P^o_L values for the compounds of interest or even on P^o_L values for other, similarly low-volatility compounds. This was overcome in part by using the G/P data from the α-pinene and cyclohexene experiments to determine P^o_L values for use (along with a set of 14 other independent polar compounds) in calculating UNIFAC vapor pressure parameters that were, in turn, used to estimate all of the needed P^o_L values. The significant degree of resultant circularity in the calculations for α-pinene and cyclohexene helped lead to the good agreement that was found between the Y_i values predicted by the model, and those measured experimentally for those two compounds. However, the model was also able to predict the aerosol yield values from β-pinene, sabinene, and Δ^3-carene, for which there was significatly less circularity in the calculations, thereby providing evidence supporting the idea that given the correct input information, SOA formation can in fact be accurately modeled as a multicomponent condensation process

Лептоспироз - современный клинико-эпидемиологический взгляд

Spitalul Raional CahulLeptospirosis has been recognized as an emerging global public health problem because of its increasing incidence in both developing and developed countries. It is a direct zoonotic disease caused by spirochetes belonging to different pathogenic species of the genus Leptospira. The majority of leptospiral infections are either sub clinical or result in very mild illness followed by recovery without further complications. However, a small proportion affecting multiple organ systems develop various complications. In such patients the clinical presentation depends upon the predominant organs involved, and the rate of fatality can be 40% or higher. Because of the protean manifestations of leptospirosis the illness is often misdiagnosed and under-reported. Although the basic principles of prevention such as source reduction, environmental sanitation, more hygienic work-related and personal practices etc., are same everywhere, there is no universal control method applicable to all epidemiological settings. Comprehensive understanding of the eco-epidemiological characteristics of a community that faces the problem of leptospirosis is an essential prerequisite for creating effective and acceptable control measures.Лептоспироз является на сегодняшний день нарастающей глобальной проблемой здравоохранения из-за увеличивающейся частоты случаев заболевания как в развитых, так и в развивающихся странах. Лептоспироз представляет cобой зоонозное заболевание, провоцируемое патогенными спирохетами рода Leptospirae. Большинство случаев инфицирования являются субклиническими или же характеризуются лёгким течением и выздоровлением без каких-либо последствий. Всё же в редких случаях наблюдается развитие тяжёлого заболевания, с поражением большого числа органов, с риском смертности, достигающей 40%. По причине неспецифической и разнообразной картины заболевание нередко ошибочно или запоздало диагностируется. Несмотря на однообразность мер предотвращения заболеваемости, направленных на уменьшение очагов, воздействие на окружающую среду, ведение работы по повышению личной гигиены и гигиены труда, до настоящего времени не разработаны универсальные методы эффективного контроля в любых эпидемиологических условиях. Глубокое понимание эко-эпидемиологических характеристик региона, столкнувшегося с проблемой лептоспироза, лежит в основе разработки специфических методов контроля

The radical character of the acenes: A density matrix renormalization group study

We present a detailed investigation of the acene series using high-level wavefunction theory. Our ab-initio Density Matrix Renormalization Group algorithm has enabled us to carry out Complete Active Space calculations on the acenes from napthalene to dodecacene correlating the full pi-valence space. While we find that the ground-state is a singlet for all chain-lengths, examination of several measures of radical character, including the natural orbitals, effective number of unpaired electrons, and various correlation functions, suggests that the longer acene ground-states are polyradical in nature.Comment: 10 pages, 8 figures, supplementary material, to be published in J. Chem. Phys. 127, 200

The Lantern Vol. 10, No. 1, December 1941

• Misty • The Evils of Initiations • Ursinus, Fifty Years Ago • My Conversion • Our Gang • From Rabble to Royalty • So You Want to be an Editor! • Tempo • A Musician\u27s Allegory • Flotsam • The Years • Common Things • Sea Moods • Aunt Agatha\u27s Pillow • Peace at Autumn Twilighthttps://digitalcommons.ursinus.edu/lantern/1025/thumbnail.jp

Sex hormone associations with breast cancer risk and the mediation of randomized trial postmenopausal hormone therapy effects

Introduction: Paradoxically, a breast cancer risk reduction with conjugated equine estrogens (CEE) and a risk elevation with CEE plus medroxyprogesterone acetate (CEE + MPA) were observed in the Women’s Health Initiative (WHI) randomized controlled trials. The effects of hormone therapy on serum sex hormone levels, and on the association between baseline sex hormones and disease risk, may help explain these divergent breast cancer findings. Methods: Serum sex hormone concentrations were measured for 348 breast cancer cases in the CEE + MPA trial and for 235 cases in the CEE trial along with corresponding pair-matched controls, nested within the WHI trials of healthy postmenopausal women. Association and mediation analyses, to examine the extent to which sex hormone levels and changes can explain the breast cancer findings, were conducted using logistic regression. Results: Following CEE treatment, breast cancer risk was associated with higher concentrations of baseline serum estrogens, and with lower concentrations of sex hormone binding globulin. However, following CEE + MPA, there was no association of breast cancer risk with baseline sex hormone levels. The sex hormone changes from baseline to year 1 provided an explanation for much of the reduced breast cancer risk with CEE. Specifically, the treatment odds ratio (95% confidence interval) increased from 0.71 (0.43, 1.15) to 0.92 (0.41, 2.09) when the year 1 measures were included in the logistic regression analysis. In comparison, the CEE + MPA odds ratio was essentially unchanged when these year 1 measures were included. Conclusions: Breast cancer risk remains low following CEE use among women having favorable baseline sex hormone profiles, but CEE + MPA evidently produces a breast cancer risk for all women similar to that for women having an unfavorable baseline sex hormone profile. These patterns could reflect breast ductal epithelial cell stimulation by CEE + MPA that is substantially avoided with CEE, in conjunction with relatively more favorable effects of either regimen following a sustained period of estrogen deprivation. These findings may have implications for other hormone therapy formulations and routes of delivery. Trial registration clinicaltrials.gov identifier: NCT00000611