The 21 cm Signature of Cosmic String Wakes

We discuss the signature of a cosmic string wake in 21cm redshift surveys. Since 21cm surveys probe higher redshifts than optical large-scale structure surveys, the signatures of cosmic strings are more manifest in 21cm maps than they are in optical galaxy surveys. We find that, provided the tension of the cosmic string exceeds a critical value (which depends on both the redshift when the string wake is created and the redshift of observation), a cosmic string wake will generate an emission signal with a brightness temperature which approaches a limiting value which at a redshift of $z + 1 = 30$ is close to 400 mK in the limit of large string tension. The signal will have a specific signature in position space: the excess 21cm radiation will be confined to a wedge-shaped region whose tip corresponds to the position of the string, whose planar dimensions are set by the planar dimensions of the string wake, and whose thickness (in redshift direction) depends on the string tension. For wakes created at $z_i + 1 = 10^3$, then at a redshift of $z + 1 = 30$ the critical value of the string tension $\mu$ is $G \mu = 6 \times 10^{-7}$, and it decreases linearly with redshift (for wakes created at the time of equal matter and radiation, the critical value is a factor of two lower at the same redshift). For smaller tensions, cosmic strings lead to an observable absorption signal with the same wedge geometry.Comment: 11 pages, 4 figures; a couple of comments added in the discussion sectio

COMPRENDO: Focus and approach

Tens of thousands of man-made chemicals are in regular use and discharged into the environment. Many of them are known to interfere with the hormonal systems in humans and wildlife. Given the complexity of endocrine systems, there are many ways in which endocrine-disrupting chemicals (EDCs) can affect the body’s signaling system, and this makes unraveling the mechanisms of action of these chemicals difficult. A major concern is that some of these EDCs appear to be biologically active at extremely low concentrations. There is growing evidence to indicate that the guiding principle of traditional toxicology that “the dose makes the poison” may not always be the case because some EDCs do not induce the classical dose–response relationships. The European Union project COMPRENDO (Comparative Research on Endocrine Disrupters—Phylogenetic Approach and Common Principles focussing on Androgenic/Antiandrogenic Compounds) therefore aims to develop an understanding of potential health problems posed by androgenic and antiandrogenic compounds (AACs) to wildlife and humans by focusing on the commonalities and differences in responses to AACs across the animal kingdom (from invertebrates to vertebrates)

DNA Oxidation Photoinduced by Norharmane Rhenium(I) Polypyridyl Complexes: Effect of the Bidentate N,N′-Ligands on the Damage Profile

ReI-polypyridyl complexes have interesting and distinctive photochemical and photosensitizing properties. This work describes the capability to induce (or photoinduce) DNA damage of three ReI-complexes with a naturally occurring alkaloid called norharmane (nHo) as ligand: [Re(CO)3(nHo)(L)]CF3SO3 where L=2,2′-bipyridine (ReBpy), phenanthroline (RePhen) or dipyrido[3,2-a:2′,3′-c]phenazine (ReDppz). The interaction of the complexes with DNA was investigated by steady-state and time-resolved spectroscopy. Data show that the mode and strength of interaction depend on the chemical structure of the bidentate ligand. The complexes show a major static contribution to the overall interaction, giving rise to the formation of noncovalent adducts with DNA, and the particular trend observed was RePhen>ReDppz>ReBpy. Photo-oxidation at the purine bases represents the major DNA damaging mechanism. RePhen also induces single-strand breaks in a yield similar to that of base damage, suggesting an additional photosensitizing pathway. We also performed the Ames test to evaluate the cytotoxic and mutagenic properties of both non-irradiated and photoexcited complexes. RePhen, but not the other complexes, turned out to be both toxic and phototoxic for the bacteria.Fil: Maisuls, Iván. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: Cabrerizo, Franco Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); ArgentinaFil: David Gara, Pedro Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Ópticas. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones Ópticas. Universidad Nacional de La Plata. Centro de Investigaciones Ópticas; ArgentinaFil: Epe, Bernd. Johannes Gutenberg Universitat Mainz; AlemaniaFil: Ruiz, Gustavo Teodosio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentin

Seeking String Theory in the Cosmos

We review the existence, formation and properties of cosmic strings in string theory, the wide variety of observational techniques that are being employed to detect them, and the constraints that current observations impose on string theory models.Comment: 25 pages; contribution for String Cosmology issue of Classical and Quantum Gravity. References added and other improvements. Matches journal versio

Cosmology of the selfaccelerating third order Galileon

In this paper we start from the original formulation of the galileon model with the original choice for couplings to gravity. Within this framework we find that there is still a subset of possible Lagrangians that give selfaccelerating solutions with stable spherically symmetric solutions. This is a certain constrained subset of the third order galileon which has not been explored before. We develop and explore the background cosmological evolution of this model drawing intuition from other even more restricted galileon models. The numerical results confirm the presence of selfacceleration, but also reveals a possible instability with respect to galileon perturbations.Comment: 30 pages, 24 figure

Phosphorus rates on yield and quality of lettuce seeds.

Because of lack of information about phosphorus fertilization in lettuce from the standpoint of seed production, this study was undertaken. The work was carried out in Botucatu, São Paulo state, Brazil, from September 25, 2003 to February 19, 2004, in order to study the influence of crescents phosphorus rates on yield and quality of lettuce seeds, cultivar Verônica. The experimental design was randomized blocks with five treatments (0; 200; 400; 600 and 800 kg ha-1 of P2O5) and five replications. The following characteristics were evaluated: seed production per plant (g plant-1), number of seeds per plant and quality (percentage of germination and seed vigor). A linear increasing was observed on production and number of seeds per plant of lettuce with phosphorus rates, but these rates did not affect the seed physiological quality evaluated on weight of 1,000 seeds (average = 0.91 g), first count of germination (98%), standard germination test (99%), seed germination speed index (68.5), seedling emergence speed index (97.0) and emerged seedlings (49.3%)

Volatility Discovery Across Stock Limit Order Book and Options Markets

Foucault [Journal of Financial Markets, 2, 99–134, 1999] provides a theoretical basis for how stock price volatility influences the aggressiveness of limit order traders. I investigate volatility discovery across stock limit order book and options markets using a broad panel of NYSE‐listed stocks from November 2007 to January 2008 and find strong evidence that, as predicted, the aggressiveness of the stock limit order book and option volatility trading Granger‐cause each other. Further, I find that the aggressiveness of the stock limit order book and option volatility trading are inversely related, which is both statistically and economically significant. © 2013 Wiley Periodicals, Inc. Jrl Fut Mark 34:934–956, 2014Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108316/1/fut21628.pd

Design considerations of high RAP-content asphalt produced at reduced temperatures

In many countries recycling of reclaimed asphalt pavement (RAP) for road surface layers is limited to a maximum of 10–30%. This is due to technical limitation of common asphalt plant but also to specifications that are still restrictive when it comes to increasing RAP in surface courses. The mistrust in this practice is mainly related to uncertainty in performance of these mixes as well as to existing fundamental issues with the mix design, especially when production temperatures are lowered. This paper analyses some of the factors affecting the design of warm asphalt mixtures for surface course layers containing 50% RAP, and suggests a framework to justify the common assumption of full blending by optimising production conditions. A control hot mix asphalt which was manufactured with 49 dmm penetration binder and asphalt mixtures containing 50% RAP produced at temperatures between 95 and 135 °C and at different mixing times were investigated in terms of volumetric properties, indirect tensile stiffness modulus, and indirect tensile strength. The high-content RAP mixtures were produced within the warm mix region by using only a very soft binder as a rejuvenator, which reduces production costs. Statistical analysis was deployed, and different models were developed to estimate degree of blending between RAP binder and rejuvenator binder, and to predict the equivalent penetration of the blend without binder extraction and recovery. The analysis results showed that the selected performance indicators correlate significantly with mixing time and temperature, and provide evidence that only in certain circumstances and if the production conditions are accurately controlled, the practical full blending approach is acceptable

Construction of non-polar mutants in Haemophilus influenzae using FLP recombinase technology

Background Nontypeable Haemophilus influenzae (NTHi) is a gram-negative bacterium that causes otitis media in children as well as other infections of the upper and lower respiratory tract in children and adults. We are employing genetic strategies to identify and characterize virulence determinants in NTHi. NTHi is naturally competent for transformation and thus construction of most mutants by common methodologies is relatively straightforward. However, new methodology was required in order to construct unmarked non-polar mutations in poorly expressed genes whose products are required for transformation. We have adapted the lambda red/FLP-recombinase-mediated strategy used in E. coli for use in NTHi. Results A cassette containing a spectinomycin resistance gene and an rpsL gene flanked by FRT sites was constructed. A PCR amplicon containing 50 base pairs of DNA homologous to the 5' and 3' ends of the gene to be disrupted and the cassette was generated, then recombineered into the target NTHi gene, cloned on a plasmid, using the lambda recombination proteins expressed in E. coli DY380. Thus, the gene of interest was replaced by the cassette. The construct was then transformed into a streptomycin resistant NTHi strain and mutants were selected on spectinomycin-containing growth media. A plasmid derived from pLS88 with a temperature sensitive replicon expressing the FLP recombinase gene under the control of the tet operator/repressor was constructed. This plasmid was electroporated into the NTHi mutant at the permissive temperature and FLP expression was induced using anhydrotetracycline. The recombinase recognizes the FRT sites and eliminates the antibiotic cassette by site-specific recombination, creating the unmarked non-polar mutation. The plasmid is cured by growth of cells at the restrictive temperature. Conclusion The products of the genes in the NTHi pilABCD operon are required for type IV pilus biogenesis and have a role in transformation. We demonstrated the utility of our methodology by the construction of a non-polar pilA mutation in NTHi strain 2019 and complementation of the mutation with a plasmid containing the pilA gene. Utilization of this approach allowed us to readily generate unmarked non-polar mutations in NTHi genes.This work was supported by NIH grants R01DC007464 to RSM, R01DC003915 to Lauren Bakaletz and a subcontract from N01AI30040 to Michael Apicella. We thank Michael Apicella for the gifts of NTHi strains 2019 and 2019 rpsL

Acute cholecystitis – early laparoskopic surgery versus antibiotic therapy and delayed elective cholecystectomy: ACDC-study

<p>Abstract</p> <p>Background</p> <p>Acute cholecystitis occurs frequently in the elderly and in patients with gall stones. Most cases of severe or recurrent cholecystitis eventually require surgery, usually laparoscopic cholecystectomy in the Western World. It is unclear whether an initial, conservative approach with antibiotic and symptomatic therapy followed by delayed elective surgery would result in better morbidity and outcome than immediate surgery. At present, treatment is generally determined by whether the patient first sees a surgeon or a gastroenterologist. We wish to investigate whether both approaches are equivalent. The primary endpoint is the morbidity until day 75 after inclusion into the study.</p> <p>Design</p> <p>A multicenter, prospective, randomized non-blinded study to compare treatment outcome, complications and 75-day morbidity in patients with acute cholecystitis randomized to laparoscopic cholecystectomy within 24 hours of symptom onset or antibiotic treatment with moxifloxacin and subsequent elective cholecystectomy. For consistency in both arms moxifloxacin, a fluorquinolone with broad spectrum of activity and high bile concentration is used as antibiotic. Duration: October 2006 – November 2008</p> <p>Organisation/Responsibility</p> <p>The trial was planned and is being conducted and analysed by the Departments of Gastroenterology and General Surgery at the University Hospital of Heidelberg according to the ethical, regulatory and scientific principles governing clinical research as set out in the Declaration of Helsinki (1989) and the Good Clinical Practice guideline (GCP).</p> <p>Trial Registration</p> <p>ClinicalTrials.gov NCT00447304</p