The Ramsey Number for 3-Uniform Tight Hypergraph Cycles

Let C(3)n denote the 3-uniform tight cycle, that is, the hypergraph with vertices v1, .–.–., vn and edges v1v2v3, v2v3v4, .–.–., vn−1vnv1, vnv1v2. We prove that the smallest integer N = N(n) for which every red–blue colouring of the edges of the complete 3-uniform hypergraph with N vertices contains a monochromatic copy of C(3)n is asymptotically equal to 4n/3 if n is divisible by 3, and 2n otherwise. The proof uses the regularity lemma for hypergraphs of Frankl and Rödl

What punishment expresses

In this article, I consider the question of what punishment expresses and propose a way of approaching the question that overcomes problems in both psychosocial and philosophical expressivist traditions. The problem in both traditions is, I suggest, the need for an adequate moral – neither moralizing nor reductive – psychology, and I argue that Melanie Klein’s work offers such a moral psychology. I offer a reconstruction of Klein’s central claims and begin to sketch some of its potential implications for an expressive account of punishment. I outline a Kleinian interpretation of modern punishment’s expression as of an essentially persecutory nature but also include depressive realizations that have generally proved too difficult for liberal modernity to work through successfully, and the recent ‘persecutory turn’ is a defence against such realizations. I conclude by considering the wider philosophical significance of a Kleinian account for the expressivist theory of punishment

Host recognition in a desert mistletoe: Early stages of development are influenced by substrate and host origin

1. In many root parasites, chemical substances from the host are necessary for the successful initiation of germination and holdfast formation, and are the basis for host recognition and localization within the rhizosphere. In contrast, bird-dispersed mistletoe seeds have no need for the chemical localization of a host, and possible mechanisms of host recognition are poorly understood. Many studies claim that mistletoes germinate readily in the absence of a host and independent of the substrate. 2. In this study, the possible occurrence of substrate dependence and host recognition in mistletoes during the establishment of Plicosepalus acaciae Zucc. seeds on Acacia raddiana Savi was tested experimentally. 3. In a laboratory experiment, no influence of substrate on germination could be found, but a significantly higher proportion of the germinated seeds developed a holdfast on natural (bark) substrate than on artificial (plastic) substrate. Moreover, the origin of the bark had a significant influence on holdfast formation frequency. 4. Host influence was additionally tested in a reciprocal transplant experiment in two field sites with genetically different populations of the same host species. Those mistletoes of local origin germinated significantly more often than their non-local counterparts. 5. These results suggest the existence of interactions between mistletoe seed and host branch on the basis of chemical cues that are active at an early stage of seedling development and are host-specific at the level of populations.Articl

Light-induced molecular change in HgI2{middle dot}As4S4: Evidence by single-crystal X-ray diffraction and Raman spectroscopy

To investigate the behavior of the As4S4 molecule within a crystal-chemical environment differing from realgar, alpha-As4S4, and its high-temperature polymorph, beta-As4S4, the effects of the light exposure on the structure of the HgI2 center dot As4S4 adduct have been studied. The structure of this compound consists of a packing of nearly linear HgI2 molecules and As4S4 cage-molecules. A crystal [V= 1295.9(4) angstrom(3)] was exposed to filtered polychromatic light (550 nm long-wavelength pass filter). A marked increase of the unit-cell volume as a function of the exposure time was observed up to V= 1338.9 angstrom(3) at 3060 min of exposure. Structure refinements indicated that the increase of the unit-cell volume is to ascribe to the formation of an increasing fraction (up to 59%) of pararealgar replacing the realgar-type molecule. After this point, further light-exposure did not cause any further increase of the lattice parameters. On the contrary, a slow, continuous decrease of the unit-cell volume down to 1292.9 angstrom(3) occurred by keeping the crystal in the dark (39 days). The "reverse" evolution of the unit-cell parameters in the dark almost overlap that observed during the light-induced process and the structural model obtained after the "dark stage" was found to be identical to that of the unaltered crystal, although the diffraction quality was lower and powder-like diffraction rings were observed together with single-crystal reflections. Apart from few peaks belonging to the original unaltered HgI2 center dot As4S4 adduct, most of the collected peaks can be assigned to beta-As4S4. This feature could indicate decomposition into micro-crystalline beta-As4S4 and HgI2; no diffraction effect ascribable to any HgI2 phase, however, was observed. Micro-Raman spectra were collected on crystals exposed to the above-mentioned wavelength light for increasing times (up to 3000 min). The peak at 274(+/- 1) cm(-1) whose intensity increases as a function of the exposure time confirms the transition from a realgar- to a pararealgar-type molecule in the HgI2 center dot As4S4 adduct

Molecular characterization of HPH-1: a mouse mutant deficient in GTP cyclohydrolase I activity

Click on the DOI link to access the article (may not be free).GTP cyclohydrolase I catalyzes the initial and rate limiting step of the biosynthesis of tetrahydrobiopterin, the cofactor for aromatic amino acid hydroxylation. The mouse mutant HPH-1, previously generated by chemical mutagenesis, shows a phenylketonuria due to decreased hepatic GTP cyclohydrolase I activity. We show that both parameters GTP cyclohydrolase I activity and tetrahydrobiopterin synthesis significantly increase after weaning, but remain reduced during the lifetime. In the wild type mouse (C57BL/6), interferon-γ and kit ligand induce GTP cyclohydrolase I activity in primed T-cells and in bone marrow-derived mast cells, respectively. The same is true for the HPH-1 mutant, but the absolute values remain lower throughout. The open reading frame of GTP cyclohydrolase I is not affected by the hph-1 mutation as shown by sequencing. Northern blot analysis demonstrates a marked decrease in the steady state mRNA level specific for GTP cyclohydrolase I

International expert opinion on the considerations for combining vosoritide and limb surgery: a modified delphi study

Background: Achondroplasia is the most common form of skeletal disorder with disproportionate short stature. Vosoritide is the first disease-specific, precision pharmacotherapy to increase growth velocity in children with achondroplasia. Limb surgery is a standard approach to increase height and arm span, improve proportionality and functionality, as well as correcting deformities. The aim of this study was to gain expert opinion on the combined use of vosoritide and limb surgery in children and adolescents with achondroplasia. Methods: An international expert panel of 17 clinicians and orthopaedic surgeons was convened, and a modified Delphi process undertaken. The panel reviewed 120 statements for wording, removed any unnecessary statements, and added any that they felt were missing. There were 26 statements identified as facts that were not included in subsequent rounds of voting. A total of 97 statements were rated on a ten-point scale where 1 was ‘Completely disagree’ and 10 ‘Completely agree’. A score of ≥ 7 was identified as agreement, and ≤ 4 as disagreement. All experts who scored a statement ≤ 4 were invited to provide comments. Results: There was 100% agreement with several statements including, “Achieve a target height, arm span or upper limb length to improve daily activities” (mean level of agreement [LoA] 9.47, range 8–10), the “Involvement of a multidisciplinary team in a specialist centre to follow up the patient” (mean LoA 9.67, range 7–10), “Planning a treatment strategy based on age and pubertal stage” (mean LoA 9.60, range 8–10), and “Identification of short- and long-term goals, based on individualised treatment planning” (mean LoA 9.27, range 7–10), among others. The sequence of a combined approach and potential impact on the physes caused disagreement, largely due to a lack of available data. Conclusions: It is clear from the range of responses that this modified Delphi process is only the beginning of new considerations, now that a medical therapy for achondroplasia is available. Until data on a combined treatment approach are available, sharing expert opinion is a vital way of providing support and guidance to the clinical community