The difference of value of cash between financially constrained and unconstrained firms

Corporate cash holding，value of cash and financial constraints are always topical issues in academic studies. Since the cash holdings are so important for the operation and investment of companies, companies can allocate appropriate funds to support the operations and conduct profitable investments only with a good level of cash holding. In addition, holding sufficient internal funds can help firms to over the hump in future. This study investigates several measures, which are used for measuring the financial constraints. Besides, the impaction of cash holdings to firms under the circumstances of both financially constrained and unconstrained are discussed. On the purpose of classifying companies as constrained and unconstrained, we use four kinds of proxies, which are annual payout ratio, firm size, debt rating (long-term) and paper rating (short-term). The samples I use in this study include the data of firms in US market, which is available on Compustat's database over the period of 2000–2014. Through conducting the random effect model and GMM model, we find that financially constrained firms usually retain more cash than financially unconstrained firms and the impact of the cash is bigger for financially constrained firms. Furthermore, the firms without external fund resource will create more value with every extra dollar reserved and increase their marginal value of cash

Quantum interferometers: principles and applications

Interference, which refers to the phenomenon associated with the superposition of waves, has played a crucial role in the advancement of physics and finds a wide range of applications in physical and engineering measurements. Interferometers are experimental setups designed to observe and manipulate interference. With the development of technology, many quantum interferometers have been discovered and have become cornerstone tools in the field of quantum physics. Quantum interferometers not only explore the nature of the quantum world but also have extensive applications in quantum information technology, such as quantum communication, quantum computing, and quantum measurement. In this review, we analyze and summarize three typical quantum interferometers: the Hong-Ou-Mandel (HOM) interferometer, the N00N state interferometer, and the Franson interferometer. We focus on the principles and applications of these three interferometers. In the principles section, we present the theoretical models for these interferometers, including single-mode theory and multi-mode theory. In the applications section, we review the applications of these interferometers in quantum communication, computation, and measurement. We hope that this review article will promote the development of quantum interference in both fundamental science and practical engineering applications.Comment: 64 pages, 40 figures. Comments are welcom

Distribution of nucleosides in populations of Cordyceps cicadae

A rapid HPLC method had been developed and used for the simultaneous determination of 10 nucleosides (uracil, uridine, 2'-deoxyuridine, inosine, guanosine, thymidine, adenine, adenosine, 2'-deoxyadenosine and cordycepin) in 10 populations of Cordyceps cicadae, in order to compare four populations of Ophicordyceps sinensis and one population of Cordyceps militaris. Statistical analysis system (SAS) 8.1 was used to analyze the nucleoside data. The pattern of nucleoside distribution was analyzed in the sampled populations of C. cicadae, O. sinensis and C. militaris, using descriptive statistical analysis, nested analysis and Q cluster analysis. The total amount of the 10 nucleosides in coremium was 1,463.89-5,678.21 mu g/g in 10 populations of C. cicadae, 1,369.80-3,941.64 mu g/g in sclerotium. The average contents of the 10 analytes were 4,392.37 mu g/g and 3,016.06 mu/g in coremium and sclerotium, respectively. The coefficient of variation (CV) of nucleosides ranged from 8.36% to 112.36% in coremium of C. cicadae, and from 10.77% to 155.87% in sclerotium of C. cicadae. The CV of the nucleosides was wide within C. cicadae populations. The nested variation analysis by the nine nucleosides' distribution indicated that about 42.29% of the nucleoside variability in coremium was attributable to the differentiation among populations, and the remaining 57.71% resided in the populations. It was also shown that about 28.94% of the variation in sclerotium was expressed between populations, while most of the variation (71.06%) corresponded to the populations

Cityscape protection using VR and eye tracking technology

Abstract(#br)The traditional method for reconstructing cityscape relies greatly on the subjective judgment of designers, which makes the cityscape simple and homogenized. This paper aims to propose a new integrated approach to protect and design cityscape based on virtual reality (VR) and eye tracking technology. Through the integration and quantification of the eye tracking data and the protocol analysis data in the VR environment, this research has revealed the mechanism of identifying the cityscape features, and discovered the differences in the perception of the cityscape features by different people, thus proposing the multi-cultural integrated strategy for protecting cityscape. This research is of great significance for building a human-oriented scientific planning and protection method and promoting the application of cutting-edge digital technology in the field of smart city governance

Kosterlitz-Thouless melting of magnetic order in the triangular quantum Ising material TmMgGaO4

Frustrated magnets hold the promise of material realizations of exotic phases of quantum matter, but direct comparisons of unbiased model calculations with experimental measurements remain very challenging. Here we design and implement a protocol of employing many-body computation methodologies for accurate model calculations-of both equilibrium and dynamical properties-for a frustrated rare-earth magnet TmMgGaO4 (TMGO), which explains the corresponding experimental findings. Our results confirm TMGO is an ideal realization of triangular-lattice Ising model with an intrinsic transverse field. The magnetic order of TMGO is predicted to melt through two successive Kosterlitz-Thouless (KT) phase transitions, with a floating KT phase in between. The dynamical spectra calculated suggest remnant images of a vanishing magnetic stripe order that represent vortex-antivortex pairs, resembling rotons in a superfluid helium film. TMGO therefore constitutes a rare quantum magnet for realizing KT physics, and we further propose experimental detection of its intriguing properties. TmMgGaO4 is one of a number of recently-synthesized quantum magnets that are proposed to realize important theoretical models. Here the authors demonstrate the agreement between detailed experimental measurements and state-of-the-art predictions based on the 2D transverse-field triangular lattice Ising model

The impact of medical insurance on medical expenses for older Chinese: Evidence from the national baseline survey of CLHLS.

With the deepening population aging process in China, the medical expenses of older adults has become a widespread concerned. Medical insurance is a major source of Chinese medical financing and payment. The study aims to understand the current status of medical expenses for older adults and explore the effect of different types of health insurance on medical expenses in China.The data came from the Chinese Longitudinal Health Longevity Survey (CLHLS) in 2014. The Kruskal-Wallis test and general multivariate linear regression model were applied to analyze the current situation and to explore how medical insurance as the main payment impacts medical expenses.A total of 4376 older participants were included in this study. The median of medical expenses of a total was 1500 Yuan per year. The proportions of participants who had the urban employee-based basic medical insurance (UE-BMI), the urban residents basic medical insurance (UR-BMI), the new rural cooperative medical insurance scheme (NCMS), and the commercial medical insurance were 10.8%, 8.4%, 72.7%, and 0.9%, respectively. 34.8% of older adults paid the health care service via the NCMS and 11.9% paid via the UE-BMI. Participating in the NCMS and UR-BMI are significantly related to the level of the medical fees of older adults. UE-BMI, UR-BMI, and NCMS as main payment eased the pressure of medical expenses.The influence of different types of medical insurances as main payments on the medical expenses of older adults is varied. Implementation of medical insurance should be taken to further relieve the medical expenses of older adults

Spectrally resolved Franson interference

Franson interference can be used to test the nonlocal features of energy-time entanglement and has become a standard in quantum physics. However, most of the previous Franson interference experiments were demonstrated in the time domain, and the spectral properties of Franson interference have not been fully explored. Here, we theoretically and experimentally demonstrate spectrally resolved Franson interference using biphotons with different correlations, including positive correlation, negative correlation, and non-correlation. It is found that the joint spectral intensities of the biphotons can be modulated along both the signal and idler directions, which has potential applications in generating high-dimensional frequency entanglement and time-frequency grid states. This work may provide a new perspective for understanding the spectral-temporal properties of the Franson interferometer.Comment: 6+7pages, 3+1 figure

Pre-Late Eocene position of the Lüchun-Jinping microblock in western Yangtze Craton: constraints from Eocene-Oligocene lamprophyres in southeastern Tibet

The tectono-magmatic history of the Lüchun-Jinping microblock and its possible affinity with the Yangtze Craton are important elements for the reconstruction of Cenozoic plate tectonics in southeastern Tibet. In order to constrain the affinity and decipher the pre-Cenozoic paleopositon of the Lüchun-Jinping microblock, we focused on the petrogenesis of Eocene-Oligocene lamprophyres in the Lüchun-Jinping microblock. The lamprophyres yield zircon Usingle bondPb ages of 34.7–33.3 Ma and exhibit potassic-ultrapotassic features with elevated K2O/Na2O (1.4–4.0) ratios. They are characterized by high concentrations of compatible elements (e.g., Cr = 187–692 ppm, Ni = 31–218 ppm), large-ion-lithophile elements and light rare-earth elements enrichment, high-field-strength elements depletion, and high radiogenic isotopic values, i.e. (87Sr/86Sr)i = 0.7063–0.7078 and εNd(t) = −3.9 to −2.4. Combined with the low Nb/U ratios, these features suggest that the lithospheric mantle source was metasomatized by subduction-related fluids beneath the Lüchun-Jinping microblock. The relatively high Rb/Sr ratios and high heavy rare-earth element contents indicate that these lamprophyres were derived from partial melting of a phlogopite-bearing lherzolite within the spinel stability field. The parental magmas have experienced fractional crystallization of olivine and clinopyroxene during emplacement. Comprehensive comparisons between the lamprophyres from the Lüchun-Jinping microblock and the potassic-ultrapotassic mafic rocks from the western Yangtze Craton indicate that the Lüchun-Jinping microblock can be regarded as a dismembered part of the western Yangtze Craton due to continental extrusion and Cenozoic sinistral displacement. The compositional trends of the potassic-ultrapotassic mafic rocks suggest that the palaeogeographic position of the Lüchun-Jinping microblock was near the Dali area (west of the Binchuan) and close to the Jinshajiang suture zone before the Cenozoic

Dirac quantum spin liquid emerging in a kagome-lattice antiferromagnet

Emerging quasi-particles with Dirac dispersion in condensed matter physics are analogous to their cousins in high-energy physics in that both of them can be described by the Dirac equation for relativistic electrons. Recently, these Dirac fermions have been widely found in electronic systems, such as graphene and topological insulators. At the conceptual level, since the charge is not a prerequisite for Dirac fermions, the emergence of Dirac fermions without charge degree of freedom has been theoretically predicted to be realized in Dirac quantum spin liquids. In such case, the Dirac quasiparticles are charge-neutral and carry a spin of 1/2, known as spinons. Despite of theoretical aspirations, spectra evidence of Dirac spinons remains elusive. Here we show that the spin excitations of a kagome antiferromagnet, YCu$_3$(OD)$_6$Br$_2$[Br$_{x}$(OD)$_{1-x}$], are conical with a spin continuum inside, which are consistent with the convolution of two Dirac spinons. The spinon velocity obtained from the spin excitations also quantitatively reproduces the low-temperature specific heat of the sample. Interestingly, the locations of the conical spin excitations differ from those calculated by the nearest neighbor Heisenberg model, suggesting an unexpected origin of the Dirac spinons. Our results thus provide strong spectra evidence for the Dirac quantum-spin-liquid state emerging in this kagome-lattice antiferromagnet.Comment: 7 pages, 4 figure

Diet and Cell Size Both Affect Queen-Worker Differentiation through DNA Methylation in Honey Bees (Apis mellifera, Apidae)

Young larvae of the honey bee (Apis mellifera) are totipotent; they can become either queens (reproductives) or workers (largely sterile helpers). DNA methylation has been shown to play an important role in this differentiation. In this study, we examine the contributions of diet and cell size to caste differentiation.We measured the activity and gene expression of one key enzyme involved in methylation, Dnmt3; the rates of methylation in the gene dynactin p62; as well as morphological characteristics of adult bees developed either from larvae fed with worker jelly or royal jelly; and larvae raised in either queen or worker cells. We show that both diet type and cell size contributed to the queen-worker differentiation, and that the two factors affected different methylation sites inside the same gene dynactin p62.We confirm previous findings that Dnmt3 plays a critical role in honey bee caste differentiation. Further, we show for the first time that cell size also plays a role in influencing larval development when diet is kept the same