Lyapunov Control on Quantum Open System in Decoherence-free Subspaces

A scheme to drive and manipulate a finite-dimensional quantum system in the decoherence-free subspaces(DFS) by Lyapunov control is proposed. Control fields are established by Lyapunov function. This proposal can drive the open quantum system into the DFS and manipulate it to any desired eigenstate of the free Hamiltonian. An example which consists of a four-level system with three long-lived states driven by two lasers is presented to exemplify the scheme. We have performed numerical simulations for the dynamics of the four-level system, which show that the scheme works good.Comment: 5 pages, 6 figure

Not an open cluster after all: the NGC 6863 asterism in Aquila

Shortly after birth, open clusters start dissolving; gradually losing stars into the surrounding star field. The time scale for complete disintegration depends both on their initial membership and location within the Galaxy. Open clusters undergoing the terminal phase of cluster disruption or open cluster remnants (OCRs) are notoriously difficult to identify. From an observational point, a combination of low number statistics and minimal contrast against the general stellar field conspire to turn them into very challenging objects. To make the situation even worst, random samples of field stars often display features that may induce to classify them erroneously as extremely evolved open clusters. In this paper, we provide a detailed study of the stellar content and kinematics of NGC 6863, a compact group of a few stars located in Aquila and described by the POSS as a non existent cluster. Nonetheless, this object has been recently classified as OCR. The aim of the present work is to either confirm or disprove its OCR status by a detailed star-by-star analysis. The analysis is performed using wide-field photometry in the UBVI pass-band, proper motions from the UCAC3 catalogue, and high resolution spectroscopy as well as results from extensive $N$-body calculations. Our results show that the four brightest stars commonly associated to NGC 6863 form an asterism, a group of non-physically associated stars projected together, leading to the conclusion that NGC 6863 is not a real open cluster.Comment: 10 pages, 8 eps figure, in press in Astronomy and Astrophysis. Abstract shortened to fit i

First-order magnetic and structural phase transitions in Fe1+y_{1+y}Sex_xTe1−x_{1-x}

We use bulk magnetic susceptibility, electronic specific heat, and neutron scattering to study structural and magnetic phase transitions in Fe$_{1+y}$Se% $_x$Te$_{1-x}$. Fe$_{1.068}$Te exhibits a first order phase transition near 67 K with a tetragonal to monoclinic structural transition and simultaneously develops a collinear antiferromagnetic (AF) order responsible for the entropy change across the transition. Systematic studies of FeSe$$Te$_x$ system reveal that the AF structure and lattice distortion in these materials are different from those of FeAs-based pnictides. These results call into question the conclusions of present density functional calculations, where FeSe$_{1-x}$Te$_x$ and FeAs-based pnictides are expected to have similar Fermi surfaces and therefore the same spin-density-wave AF order.Comment: 5 pages, 3 figure

Demography of SDSS early-type galaxies from the perspective of radial color gradients

We have investigated the radial g-r color gradients of early-type galaxies in the Sloan Digital Sky Survey (SDSS) DR6 in the redshift range 0.00<z<0.06. The majority of massive early-type galaxies show a negative color gradient (red-cored) as generally expected for early-type galaxies. On the other hand, roughly 30 per cent of the galaxies in this sample show a positive color gradient (blue-cored). These "blue-cored" galaxies often show strong H beta absorption line strengths and/or emission line ratios that are indicative of the presence of young stellar populations. Combining the optical data with Galaxy Evolution Explorer (GALEX) UV photometry, we find that all blue-cored galaxies show UV-optical colors that can only be explained by young stellar populations. This implies that most of the residual star formation in early-type galaxies is centrally concentrated. Blue-cored galaxies are predominantly low velocity dispersion systems. A simple model shows that the observed positive color gradients (blue-cored) are visible only for a billion years after a star formation episode for the typical strength of recent star formation. The observed effective radius decreases and the mean surface brightness increases due to this centrally-concentrated star formation episode. As a result, the majority of blue-cored galaxies may lie on different regions in the Fundamental Plane from red-cored ellipticals. However, the position of the blue-cored galaxies on the Fundamental Plane cannot be solely attributed to recent star formation but require substantially lower velocity dispersion. We conclude that a low-level of residual star formation persists at the centers of most of low-mass early-type galaxies, whereas massive ones are mostly quiescent systems with metallicity-driven red cores.Comment: 15 pages, 19 figures, accepted for publication in ApJ

Extra-hepatic fascioliasis with peritoneal malignancy tumor feature

Fascioliasis is a zoonose parasitic disease caused by Fasciola hepatica and Fasciola gigantica and is widespread in most regions of the world. Ectopic fascioliasis usually caused by juvenile Fasciola spp., but in recent years a few cases of tissue-embedded ova have been reported from different endemic areas. A 79-year-old Iranian man resident in Eird-e-Mousa village from Ardabil Province, north-west of Iran, complained with abdominal pain, nausea, and intestinal obstruction symptoms referred to Ardabil Fatemi hospital. In laparotomy multiple intestinal masses with peritoneal seeding resembling of a malignant lesion were seen. After appendectomy and peritoneal mass biopsy with numerous intraperitoneal adenopathy, paraffin embedded blocks were prepared from each tissues. A blood sample was taken from the patient 5 months later for serological diagnosis. Histopathological examination of sections showed fibrofatty stroma with dense mixed inflammatory cells infiltration and fibrosis in peritoneal masses. Large numbers of ova of Fasciola spp. were noted with typical circumscribed granulomas. Despite of anti-fasciola treatment, IHA test for detecting anti F. hepatica antibodies was positive 5 months after surgery with a titer of 1/128. Due to multiple clinical manifestation of extra-hepatic fascioliasis, its differential diagnosis from intraperitoneal tumors or other similar diseases should be considered

The Effects of Self-development, Self-therapy, and Self-presentation Motivations on Quality of Life, Visitor Loyalty, and Omnivorous Cultural Engagement through Visitor Satisfaction in Art Museums: Examining the Moderation Effect of Age and Attitude toward SNS Posting

This study investigates the fulfillment of self-motivation including self-development, self-therapy, and self-presentation on the outcomes such as subjective quality of life, omnivorous cultural engagement, and visitor loyalty via visitor satisfaction in art museums. The analyses on 285 valid survey responses demonstrated that fulfillment of self-development and self-therapy needs have significant positive influence on visitor satisfaction. The effect of fulfilling self-presentation need on visitor satisfaction was found to be moderated by attitude toward SNS posting, while the age factor, based on generations, did not show a significant moderation effect. It was also found that visitor satisfaction positively influences visitor loyalty, including intentions of revisit and recommendation. Increased satisfaction also enhances subjective QOL and omnivorous cultural engagement among art museum visitors, implying promising collaboration among cultural arts institutions. The findings have both theoretical and practical implications for enhancing visitor experiences and promoting diverse cultural engagement. Limitations and future research directions are also discussed

Testing the hyperfunction theory of ageing in Caenorhabditis elegans

Ageing research in model organisms has accomplished great strides in finding genes and pathways that modulate the ageing process. However, the mechanism through which organisms age still remains a mystery. An influential ageing theory views ageing as the result of damage accumulation throughout an organism’s lifespan, which eventually accumulates to noxious levels causing death. In this thesis we will explore an alternative theory proposed by M. Blagosklonny. The hyperfunction theory postulates that ageing is the result of the non-adaptive continuation of developmental and reproductive programmes in late adulthood. Thus, programmes that promote growth and reproductive fitness become quasi-programmes in later life that result in age-related pathologies, some of which cause death. In this thesis we examined two reproductive pathologies, yolk accumulation and gonad degeneration, to try to understand their causes and to test their role in age-related mortality. A clear example of a quasi-programme in ageing worms is the run-on of yolk production in post-reproductive worms. During reproduction yolk is synthesized in the intestine to be transported to oocytes and provision embryogenesis. After reproduction ceases yolk protein accumulates in the body cavity of the worm. We found that yolk proteins accumulate to high levels during ageing. However, RNAi abrogation of vitellogenesis did not increase lifespan, implying that yolk protein accumulation does not cause mortality. Gonad disintegration provides an intriguing example of how quasi-programmes can cause pathology via atrophy. We found that gonad disintegration, which occurs in post-reproductive hermaphrodite worms, is apoptosis dependant. At least half of all germ cells undergo “physiological” programmed cell death. Our results imply that the apoptotic program that ensures reproductive fitness to support oocyte growth continues in older worms giving rise to pathology

The exactness of a general Skoda complex

We show that a Skoda complex with a general plurisubharmonic weight function is exact if its 'degree' is sufficiently large. This answers a question of Lazarsfeld and implies that not every integrally closed ideal is equal to a multiplier ideal even if we allow general plurisubharmonic weights for the multiplier ideal, extending the result of Lazarsfeld and Lee \cite{LL}.Comment: References added, exposition streamlined, to appear in Michigan Mathematical Journa