bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detection and identification ofLactobacillus helveticusbacteriophages by PCR
Authors: Zago Miriam , Rossetti Lia , Reinheimer Jorge , Carminati Domenico , Giraffa Giorgio 
Published: May 2008

A PCR protocol for detection ofLactobacillus helveticusbacteriophages was optimized. PCR was designed taking into account the sequence of thelysgene of temperate bacteriophage Φ-0303 and optimized to obtain a fragment of 222 bp using differentLb. helveticusphages from our collection. PCR was applied to total phage DNA extracted from 53 natural whey starters used for the production of Grana cheese and all gave the expected fragment. The presence of actively growing phages in the cultures was verified by traditional tests. Several PCR products of thelysgene were sequenced and aligned. The resulting sequences showed variable heterogeneity between the phages.
Dairy maturation of milk used in the manufacture of Parmigiano-Reggiano cheese: effects on physico-chemical characteristics, rennet-coagulation aptitude and rheological properties
Authors: Malacarne Massimo , Summer Andrea , Formaggioni Paolo , Franceschi Piero , Sandri Sandro , Pecorari Mauro , Vecchia Paola , Mariani Primo 
Published: May 2008

The aim of this research was to study the effects of dairy maturation on the physico-chemical characteristics and technological properties of milk used for Parmigiano-Reggiano cheese manufacture. Three different operating conditions (CF1, CF2 and CF3) were considered. Full cream milk from the evening milking was stored on the farm and delivered to the cheese factory in churns (CF1) or in thermoregulated tanks at a temperature not lower than 18°C (CF2 and CF3). The natural creaming (10–12 h overnight) was performed in a traditional large flat vat containing 10–12 hl (CF1 and CF2) or in thermoregulated large flat vats containing 60 hl at about 15°C (CF3). Twenty-four, 24 and 22 maturation trials were performed in CF1, CF2, and CF3, respectively, during 2 consecutive years. A significant increase (P⩽0·05) in pH during the maturation of milk was observed in CF1 and CF2. The increase of pH was higher (P⩽0·05) in CF1 than CF2 and CF3. The values of titratable acidity were higher (P⩽0·05) in partially skimmed evening (PS) milk than in full cream (FC) milk in each operative condition. The increase observed in CF2 was higher than those reported in CF1 and CF3. Compared with FC milk, PS milk showed lower values (P⩽0·05) of casein and casein number and higher contents (P⩽0·05) of whey proteins and, particularly, proteose-peptone. The increase of proteose-peptone – per 100 g SNF or 100 g casein – was significantly higher (P⩽0·05) in CF1 than in CF2 and, in particular, than in CF3. A higher increase (P⩽0·05) of resistance to compression was observed in CF1 with respect to CF3. CF2 variation was not different with respect to either CF1 or CF3. Variation of the difference between PS and FC milks (PS-FC) in pH, TBC and fat were clearly lower in CF3 than CF1. This means that the control of milk temperature throughout the whole maturation phase offers a greater control of both microbial development and extent of creaming.
Parasite interactions in natural populations: insights from longitudinal data
Authors: TELFER S. , BIRTLES R. , BENNETT M. , LAMBIN X. , PATERSON S. , BEGON M. 
Published: May 2008

SUMMARYThe physiological and immunological state of an animal can be influenced by current infections and infection history. Consequently, both ongoing and previous infections can affect host susceptibility to another parasite, the biology of the subsequent infection (e.g. infection length) and the impact of infection on host morbidity (pathology). In natural populations, most animals will be infected by a succession of different parasites throughout the course of their lives, with probably frequent concomitant infections. The relative timing of different infections experienced by a host (i.e. the sequence of infection events), and the effects on factors such as host susceptibility and host survival, can only be derived from longitudinal data on individual hosts. Here we review some of the evidence for the impact of co-infection on host susceptibility, infection biology and pathology focusing on insights obtained from both longitudinal studies in humans and experiments that explicitly consider the sequence of infection. We then consider the challenges posed by longitudinal infection data collected from natural populations of animals. We illustrate their usefulness using our data of microparasite infections associated with field vole (Microtus agrestis) populations to examine impacts on susceptibility and infection length. Our primary aim is to describe an analytical approach that can be used on such data to identify interactions among the parasites. The preliminary analyses presented here indicate both synergistic and antagonistic interactions between microparasites within this community and emphasise that such interactions could have significant impacts on host-parasite fitness and dynamics.
Immune responses during helminth-malaria co-infection: a pilot study in Ghanaian school children
Authors: HARTGERS FRANCA C. , OBENG BENEDICTA B. , BOAKYE DANIEL , YAZDANBAKHSH MARIA 
Published: May 2008

SUMMARYMalaria and helminth infections have a shared geographical distribution and therefore co-infections are frequent in tropical areas of the world. Human populations of helminth and malaria co-infection have shown contradictory results for the course of malarial infection and disease, possibly depending on the type of helminth studied, the intensity of helminth infection and the age of the study population. Although immunological studies might clarify the underlying mechanisms of protection or increased susceptibility, there are very few studies that have looked at immunological parameters in helminth and malaria co-infection. After discussing the available immunological data on co-infection, we describe a pilot study performed in Ghanaian school children where we compare anti-malarial responses in children living in an urban area, where the prevalence of helminth andPlasmodium falciparuminfections was low, with that of children living in a rural area with high prevalence of helminth andPlasmodium falciparuminfections.
Frequency ofToxoplasma gondiiinfection in sheep from a tropical zone of Mexico and temporal analysis of the humoral response changes
Authors: CABALLERO-ORTEGA H. , QUIROZ-ROMERO H. , OLAZARÁN-JENKINS S. , CORREA D. 
Published: May 2008

SUMMARYAn indirect ELISA and an immunoblot were standardized to detect anti-Toxoplasma gondiiantibodies in sheep, and were compared with a commercial ELISA as reference. Sensitivity was 92·0 and 96·0%, and specificity 88·0 and 75·0%, respectively. Then the serum samples of 103 sheep on a ranch located in the Eastern region of Mexico were analysed. A frequency ranging from 77 to 84% was observed, with a heterogeneous pattern among the animals by immunoblotting. Ten months later 56 sheep were sampled and tested again. Six animals became negative while 1 case was negative the first time and strongly positive 10 months later. Considering this to be a new case we calculated an incidence rate of 2·1% (CI95%0·6–4·8%). IgG avidity ELISA was performed on 36 positive samples, 33 being of high-avidity at both times; slight increases in 2 samples and conservation of low-avidity in 1 sheep were also observed. Higher prevalence rates of toxoplasmosis in a moist warm compared to a cold atmosphere was attributed to the long viability ofT. gondiioocysts. This may explain the high frequency ofT. gondiiin this region, which apparently has favourable climatic conditions for the transmission of this protozoan, besides the presence of both domestic and wild cats.
Haemophilus influenzae colonization and its risk factors in children aged <2 years in northern India
Authors: SEKHAR S. , CHAKRABORTI A. , KUMAR R. 
Published: May 2008

SUMMARYThe disease burden and the age group of children most affected by Haemophilus influenzae remain controversial particularly in many countries of South Asia. Nasopharyngeal carriage of H. influenzae can indicate the transmission dynamics in these settings. In a prospective population-based study, nasopharyngeal swabs from 1000 children aged <2 years, belonging to various socioeconomic groups from rural and urban areas of northern India were taken. The prevalence of H. influenzae carriage was found to be 11·2%. Among these isolates, 69% belonged to type b and the rest were non-typable. The age group most affected was 18–21 months. The carriage rate was influenced by age and socioeconomic factors namely type of housing, overcrowding, and season. Hib carriage is quite common in northern India and it is associated with age, type of housing, overcrowding, and season. Since carriage gets established early, Hib vaccination should target children in early infancy.
Enteric outbreaks in long-term care facilities and recommendations for prevention: a review
Authors: GREIG J. D. , LEE M. B. 
Published: May 2008

SUMMARYOutbreaks of enteric illness in long-term care facilities (LTCFs) were reviewed to identify preventative recommendations. Systematic review methodology identified outbreak reports of gastrointestinal illness in LTCFs either published or that occurred from January 1997 to June 2007. The inclusion criteria captured 75 outbreaks; 23 (31%) associated with bacterial agents and 52 (69%) with viral agents. Transmission was mainly foodborne (52%) for those of bacterial origin and person-to-person (71%) for viral outbreaks. Norovirus infection was associated with 58% of hospitalizations. Sixty deaths were reported, about half from Salmonella infections. Recommendations for foodborne outbreaks emphasized appropriate sourcing and preparation of eggs, staff training, and temperature control during food preparation. Recommendations from outbreaks transmitted person-to-person centred on controlling residents' movements, effective environmental cleaning and disinfection, cancelling social events and restricting visitors, excluding ill staff, encouraging effective hand hygiene, and preventing cross-contamination through gloving and gowning. In none of the 75 published outbreak reports were the suggested recommendations evaluated for effectiveness in controlling the outbreak. Applied research of this type could greatly help in the acceptance of prevention and control strategies.
METALLURGY, MAYAPAN, AND THE POSTCLASSIC MESOAMERICAN WORLD SYSTEM
Authors: Paris Elizabeth H. 
Published: May 2008

AbstractResidents of Mayapan produced and consumed metal artifacts through long-distance commercial exchange networks in the Postclassic Mesoamerican world system. In this paper, I perform a stylistic and typological analysis of metal artifacts and debris from lost-wax casting from recent excavations at Mayapan, with reference to previously excavated collections by the Carnegie Institution of Washington, DC. The distribution of metal artifacts suggests that metal objects were not sumptuary goods restricted to elites, but luxury goods availble to those who could afford them. I then compare Mayapan with other sites in the Postclassic Mesoamerican world system that were involved in the interregional distribution of metal artifacts. Although Mayapan did not have local sources of native metal or a longstanding traditions of metalworking, it was able to use its economic influence in the world system to obtain and create metal objects specific to its needs.
Search for extrasolar planets with high-precision relative astrometry
by ground-based and single-aperture observations
Authors: Roell Tristan , Seifahrt Andreas , Neuhäuser Ralph 
Published: May 2008

AbstractWe present our search program for substellar companions using high-precision
relative astronomy. Due to its orbital motion around the star, an unseen
substellar companion would produce a periodic “wobble” of
the host star, which is the astrometric signal of the unseen companion. By
measuring the separation between the components of stellar double and triple
systems, we want to measure this astrometric signal of a possible unseen
companion indirectly as a relative and periodic change of these separations.
Using a new observation mode (the “cube-mode”) where the
frames were directly saved in cubes with nearly no loss of time during the
readout, an adaptive optics system to correct for atmospheric noise and an
infrared narrow band filter in the near infrared to suppress differential
chromatic refraction (DCR) effects we achieve for our first target (the double
star HD 19994) a relative precision for the separation measurements of about
100. . . 150μas per epoch. To reach a precision in the μas-regime, we use a statistical approach. We take
several thousand frames per target and epoche and after a verification of a
Gaussian distribution the measurement precision can be calculated as the
standard deviation of our measurements divided by the square root of the number
of Gaussian distributed measurements. Our first observed target is the stellar
binary HD 19994 A & B, where the A component has a known radial
velocity planet candidate.
Closure phase studies toward direct detection of light from hot Jupiters
Authors: Zhao Ming , Monnier John D. , ten Brummelaar Theo , Pedretti Ettore , Thureau Nathalie 
Published: May 2008

AbstractPrecision closure phase measurements obtained with ground-based long baseline optical interferometers is a promising way to directly detect light from nearby hot Jupiters. Here we present our closure phase simulations for the CHARA array for several bright hot Jupiters, υ And b, 51 Peg b, and τ Boo b. The maximum possible closure phase signals from these hot Jupiters are very small, for example, only ∼0.17 degrees for υ And b, requiring very high precision and stable closure phase measurements. We present preliminary results of a closure phase study on test object β Tau and hot Jupiter system υ And, both obtained with the MIRC instrument at the CHARA array. We demonstrate that directly detecting the light from hot Jupiters is feasible using high precision closure phase measurements obtained by CHARA-MIRC along with its sub-milli-arcsecond resolution, although challenges remain.
Photometric observation of the transiting exoplanet WASP-1b
Authors: Wang Xiao-bin , Cameron Andrew Collier , Gu Sheng-hong , Zhang Li-yun 
Published: May 2008

AbstractThe extra-solar planet WASP-1b, discovered by SuperWASP consortium in 2006, was observed through R filter using the 1-meter telescope with CCD camera at Yunnan Observatory on November 11, 2006. The systematic errors in photometric data were reduced by means of Tamuz et al. (2005) and Collier Cameron et al. (2006)'s algorithms. In order to estimate the parameters of the system, the MCMC (Markov Chain Monte Carlo) analysis is applied to fit the observed light curve. The following parameters of the system are derived: Rp=1.44RJ, Mp=0.88MJ, R*=1.52R⊙, a=0.0396AU. The new parameters of the planet imply its low density, which agrees to the previous results.
Observational window functions in planet transit searches
Authors: von Braun Kaspar , Ciardi David R. 
Published: May 2008

AbstractWindow functions describe, as a function of orbital period, the probability that an existing planetary transit is detectable in one's data for a given observing strategy. We show the dependence of this probability upon several strategy and astrophysical parameters, such as length of observing run, observing cadence, length of night, and transit duration. The ability to detect a transit is directly related to the intrinsic noise of the observations. In our simulations of the window function, we explicitly address non-correlated (white) noise and correlated (red) noise and discuss how these two different noise components affect window functions in different manners.
Cadence optimisation and exoplanetary parameter sensitivity
Authors: Kane Stephen R. , Ford Eric B. , Ge Jian 
Published: May 2008

AbstractTo achieve maximum planet yield for a given radial velocity survey, the observing strategy must be carefully considered. In particular, the adopted cadence can greatly affect the sensitivity to exoplanetary parameters such as period and eccentricity. Here we describe simulations which aim to maximise detections based upon the target parameter space of the survey.
The astrometric data reduction software (ADRS) and error budget for PRIMA
Authors: Elias N. M. , Tubbs R. N. , Köhler R. , Reffert S. , Stilz I. , Launhardt R. , de Jong J. , Quirrenbach A. , Delplancke F. , Henning Th. , Queloz D. ,   ESPRI Consortium
Published: May 2008

AbstractThe Astrometric Data-Reduction Software (ADRS) processes fringe, delay, environmental, and calibration data for PRIMA narrow-angle astrometry. It is automated software designed to provide fully-calibrated differential delays and separation angles. The ADRS is divided into on-line and off-line processing. The former deals with calibration and data compression, while the latter applies corrections and calculates science quantities. PRIMA is the first VLTI instrument that may require removal of long-term environmental trends. The trend identification and fitting routines are not part of the distributed on-line and off-line processing software. Instead, files containing fit parameters will be updated regularly. Coding is presently underway. The PRIMA error budget summarizes the principal sources of error in PRIMA astrometric observations.
Unveiling exoplanet families
Authors: Marchi Simone , Ortolani Sergio 
Published: May 2008

AbstractThe discovery of an increasing number of extrasolar planets (EPs) prompts the development of a planetary taxonomy. Such analysis, as in many other fields of research, is useful to identify groups of objects sharing similar traits. When applied to extrasolar planets, the taxonomy may provide a valid support for disentangling the role of the several physical parameters (semimajor axis, metallicity etc.) involved in the planetary formation processes and subsequent evolution. We present the state-of-the-art for exoplanets taxonomy obtained with hierarchical algorithms and the definition of robust clusters of planets (this is an update of the taxonomy published in Marchi 2007). The physical relevance of the exoplanet clusters along with their implications for the formation theories are also discussed. Finally, we comment on the future improvements of such analysis taking into account new algorithms and new input variables.
Thermal evolution and magnetism of terrestrial planets.
Authors: Tachinami Chihiro , Senshu Hiroki , Ida Shigeru 
Published: May 2008

AbstractWe evaluate a numerical model on the thermal evolution of terrestrial planets to estimate life-time of planetary intrinsic magnetic field for various mass planets. In this model, we take into account the pressure-dependency of density profile of the planet by using Birch-Murnaghun equation of state, and simulate thermal evolution of the planet by means of mixing length theory. According to our numerical results, the planetary mass must be between 0.1 and 1.4 Earth mass to sustain the intrinsic magnetic field for 4.5Gyr. If existence of intrinsic magnetic field were a key factor to make the planet habitable, the mass range above indicates that super-Earths would not be habitable.
Terrestrial planet formation in extra-solar planetary systems
Authors: Raymond Sean N. 
Published: May 2008

AbstractTerrestrial planets form in a series of dynamical steps from the solid component of circumstellar disks. First, km-sized planetesimals form likely via a combination of sticky collisions, turbulent concentration of solids, and gravitational collapse from micron-sized dust grains in the thin disk midplane. Second, planetesimals coalesce to form Moon- to Mars-sized protoplanets, also called “planetary embryos”. Finally, full-sized terrestrial planets accrete from protoplanets and planetesimals. This final stage of accretion lasts about 10-100 Myr and is strongly affected by gravitational perturbations from any gas giant planets, which are constrained to form more quickly, during the 1-10 Myr lifetime of the gaseous component of the disk. It is during this final stage that the bulk compositions and volatile (e.g., water) contents of terrestrial planets are set, depending on their feeding zones and the amount of radial mixing that occurs. The main factors that influence terrestrial planet formation are the mass and surface density profile of the disk, and the perturbations from giant planets and binary companions if they exist. Simple accretion models predicts that low-mass stars should form small, dry planets in their habitable zones. The migration of a giant planet through a disk of rocky bodies does not completely impede terrestrial planet growth. Rather, “hot Jupiter” systems are likely to also contain exterior, very water-rich Earth-like planets, and also “hot Earths”, very close-in rocky planets. Roughly one third of the known systems of extra-solar (giant) planets could allow a terrestrial planet to form in the habitable zone.
Observational tests of planet formation models
Authors: Sozzetti A. , Latham D. W. , Torres G. , Carney B. W. , Laird J. B. , Stefanik R. P. , Boss A. P. , Charbonneau D. , ODonovan F. T. , Holman M. J. , Winn J. N. 
Published: May 2008

AbstractWe summarize the results of two experiments to address important issues related to the correlation between planet frequencies and properties and the metallicity of the hosts. Our results can usefully inform formation, structural, and evolutionary models of gas giant planets.
Tidal barrier and the asymptotic mass of proto gas-giant planets
Authors: Dobbs-Dixon Ian , Li ShuLin , Lin Douglas N.C. 
Published: May 2008

AbstractAlthough late stage gap formation reduces the surface density in the vicinity of protoplanets, simulations suggest gas may continue to leak through the protoplanets tidal barrier, replenishing the gas supply and allowing protoplanets to acquire masses comparable to or larger than that of Jupiter. Global gas depletion is a possible explanation for gaseous planets with lower masses in weak-line T-Tauri disks and ice giants in our own solar system, but it is unlikely to have stalled the growth of multiple systems around nearby stars that contain relatively low-mass, close-in planets along with more massive and longer period companions. Here, we suggest a potential solution. We show that supersonic infall of surrounding gas onto a protoplanet is only possible interior to both its Bondi and Roche radii. Although the initial Bondi radius is much smaller than its Roche radius, the former overtakes the latter during its growth. Thereafter, a positive pressure gradient is required to induce the gas to enter the Roche lobe of the protoplanet and flow is significantly reduced. We present the results of analysis and numerical simulations to show that the accretion rate increases rapidly with the ratio of the protoplanets Roche to Bondi radii. Based on these results we suggest that in regions with low geometric aspect ratios gas accretion is quenched, resulting in relatively low protoplanetary masses.
Formation of heavy element rich giant planets by giant impacts
Authors: Genda H. , Ikoma M. , Guillot T. , Ida S. 
Published: May 2008

AbstractWe have performed the smoothed particle hydrodynamic (SPH) simulations of collisions between two gas giant planets. Changes in masses of the ice/rock core and the H/He envelope due to the collisions are investigated. The main aim of this study is to constrain the origin and probability of a class of extrasolar hot Jupiters that have much larger cores and/or higher core/envelope mass ratios than those predicted by theories of accretion of gas giant planets. A typical example is HD 149026b. Theoretical models of the interior of HD 149026b (Sato et al. 2005; Fortney et al. 2006; Ikoma et al. 2006) predict that the planet contains a huge core of 50-80 Earth masses relative to the total mass of 110 Earth masses. Our SPH simulations demonstrate that such a gas giant is produced by a collision with an impact velocity of typically more than 2.5 times escape velocity and an impact angle of typically less than 10 degrees, which results in an enormous loss of the envelope gas and complete accretion of both cores.