The integral cohomology rings of some p-groups

We determine the integral cohomology rings of an infinite family of p-groups, for odd primes p, with cyclic derived subgroups. Our method involves embedding the groups in a compact Lie group of dimension one, and was suggested by P H Kropholler and J Huebschmann

Some observations on the state of nutrition of infants and toddlers in Sekhukhuniland

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Chern classes and extraspecial groups

The mod-p cohomology ring of the extraspecial p-group of exponent p is studied for odd p. We investigate the subquotient ch(G) generated by Chern classes modulo the nilradical. The subring of ch(G) generated by Chern classes of one-dimensional representations was studied by Tezuka and Yagita. The subring generated by the Chern classes of the faithful irreducible representations is a polynomial algebra. We study the interplay between these two families of generators, and obtain some relations between them

Single Cell Origin of Multilineage Colonies in Culture: Evidence That Differentiation of Multipotent Progenitors and Restriction of Proliferative Potential of Monopotent Progenitors Are Stochastic Processes

In this paper, we report analysis of differentiation in human hemopoietic colonies derived from a single cell. Cord blood mononulear cells and panned My-10 antigen-positive bone marrow and cord blood cells were plated in methylcellulose medium containing erythropoietin and conditioned medium. Initially, we performed mapping studies to identify candidate colony-forming cells. Subsequently, using a micromanipulator, we transferred single cells individually to 35-mm dishes for analysis of colony formation. Cellular composition of the colony was determined by identifying all of the cells in the May-Grunwald-Giemsa stained preparation. Of 150 single candidate cells replated, 63 produced colonies. The incidences of single lineage colonies included 19 erythroid, 17 monocyte-macrophage, and 9 eosinophil colonies. There were 18 mixed hemopoietic colonies consisting of cells in two, three, four, and five lineages in varying combinations. In some instances, we noted the predominance of one lineage and the presence of very small populations of cells in a second or third lineage. These results provide evidence for the single-cell origin of human multilineage hemopoietic colonies, and are consistent with the stochastic model of stem cell differentiation in man. They also indicate that restriction of the proliferative potential of committed progenitors is a stochastic process

Why are convertible bond announcements associated with increasingly negative issuer stock returns? An arbitrage-based explanation

While convertible offerings announced between 1984 and 1999 induce average abnormal stock returns of −1.69%, convertible announcement effects over the period 2000–2008 are more than twice as negative (−4.59%). We hypothesize that this evolution is attributable to a shift in the convertible bond investor base from long-only investors towards convertible arbitrage funds. These funds buy convertibles and short the underlying stocks, causing downward price pressure. Consistent with this hypothesis, we find that the differences in announcement returns between the Traditional Investor period (1984–1999) and the Arbitrage period (2000–September 2008) disappear when controlling for arbitrage-induced short selling associated with a range of hedging strategies. Post-issuance stock returns are also in line with the arbitrage explanation. Average announcement effects of convertibles issued during the Global Financial Crisis are even more negative (−9.12%), due to a combination of short-selling price pressure and issuer, issue, and macroeconomic characteristics associated with these offerings

Distribution of TT virus (TTV), TTV-like minivirus, and related viruses in humans and nonhuman primates

AbstractTT virus (TTV) and TTV-like minivirus (TLMV) are small DNA viruses with single-stranded, closed circular, antisense genomes infecting man. Despite their extreme sequence heterogeneity (>50%), a highly conserved region in the untranslated region (UTR) allows both viruses to be amplified by polymerase chain reaction (PCR). TTV/TLMV infection was detected in 88 of 100 human plasma samples; amplified sequences were differentiated into TTV and TLMV by analysis of melting profiles, showing that both viruses were similarly prevalent. PCR with UTR primers also detected frequent infection with TTV/TLMV-related viruses in a wide range of apes (chimpanzees, gorillas, orangutans, gibbons) and African monkey species (mangabeys, drills, mandrills). These findings support the hypothesis for the co-evolution of TTV-like viruses with their hosts over the period of primate speciation, potentially analogous to the evolution of primate herpesviruses

Scale Invariance and Nonlinear Patterns of Human Activity

We investigate if known extrinsic and intrinsic factors fully account for the complex features observed in recordings of human activity as measured from forearm motion in subjects undergoing their regular daily routine. We demonstrate that the apparently random forearm motion possesses previously unrecognized dynamic patterns characterized by fractal and nonlinear dynamics. These patterns are unaffected by changes in the average activity level, and persist when the same subjects undergo time-isolation laboratory experiments designed to account for the circadian phase and to control the known extrinsic factors. We attribute these patterns to a novel intrinsic multi-scale dynamic regulation of human activity.Comment: 4 pages, three figure

Randomized clinical trial of postoperative chewing gum versus standard care after colorectal resection

Background Chewing gum may stimulate gastrointestinal motility, with beneficial effects on postoperative ileus suggested in small studies. The primary aim of this trial was to determine whether chewing gum reduces length of hospital stay (LOS) after colorectal resection. Secondary aims included examining bowel habit symptoms, complications and healthcare costs. Methods This clinical trial allocated patients randomly to standard postoperative care with or without chewing gum (sugar-free gum for at least 10 min, four times per day on days 1–5) in five UK hospitals. The primary outcome was LOS. Cox regression was used to calculate hazard ratios for LOS. Results Data from 402 of 412 patients, of whom 199 (49·5 per cent) were allocated to chewing gum, were available for analysis. Some 40 per cent of patients in both groups had laparoscopic surgery, and all study sites used enhanced recovery programmes. Median (i.q.r.) LOS was 7 (5–11) days in both groups (P = 0·962); the hazard ratio for use of gum was 0·94 (95 per cent c.i. 0·77 to 1·15; P = 0·557). Participants allocated to gum had worse quality of life, measured using the EuroQoL 5D-3L, than controls at 6 and 12 weeks after operation (but not on day 4). They also had more complications graded III or above according to the Dindo–Demartines–Clavien classification (16 versus 6 in the group that received standard care) and deaths (11 versus 0), but none was classed as related to gum. No other differences were observed. Conclusion Chewing gum did not alter the return of bowel function or LOS after colorectal resection