1,243 research outputs found
Parent–offspring conflict and its outcome under uni-and biparental care
Conflicts over parental investment are predicted to be common among family members, especially between parents and their offspring. Parent–offspring conflict has been studied in many brood-caring organisms, but whether its outcome is closer to the parental or offspring optimum is usually unknown, as is whether the presence of a second parent, a caring male partner, can affect the outcome. Here, we manipulated the initial brood size of single and paired female burying beetles to examine how many offspring are necessary to maintain parental care in the current brood. We found that mothers continued to invest in small broods even if their reproductive output would have been higher if they had discontinued their care and produced a second brood instead. Consequently, our data suggests that the offspring have the upper hand in the conflict. However, our results further show that paired females laid a second egg clutch more often and produced more offspring than single females, suggesting that the presence of a male partner shifts the conflict outcome towards the parental optimum. This latter result not only is a novel aspect of parent–offspring theory, but also represents an additional factor that might explain the evolution of biparental care
Competition of fusion and quasi-fission in the reactions leading to production of the superheavy elements
The mechanism of fusion hindrance, an effect observed in the reactions of
cold, warm and hot fusion leading to production of the superheavy elements, is
investigated. A systematics of transfermium production cross sections is used
to determine fusion probabilities. Mechanism of fusion hindrance is described
as a competition of fusion and quasi-fission. Available evaporation residue
cross sections in the superheavy region are reproduced satisfactorily. Analysis
of the measured capture cross sections is performed and a sudden disappearance
of the capture cross sections is observed at low fusion probabilities. A
dependence of the fusion hindrance on the asymmetry of the projectile-target
system is investigated using the available data. The most promising pathways
for further experiments are suggested.Comment: 8 pages, 7 figures, talk presented at 7th International
School-Seminar on Heavy-Ion Physics, May 27 - June 1, 2002, Dubna, Russi
Five-Year Longitudinal Assessment (2008 to 2012) of E-101 Solution Activity against Clinical Target and Antimicrobial-Resistant Pathogens
This study summarizes the topical E-101 solution susceptibility testing results for 760 Gram-positive and Gram-negative target pathogens collected from 75 U.S. sites between 2008 and 2012 and 103 ESKAPE pathogens. E-101 solution maintained potent activity against all bacterial species studied for each year tested, with MICs ranging from <0.008 to 0.25 ÎĽg porcine myeloperoxidase (pMPO)/ml. These results confirm that E-101 solution retains its potent broad-spectrum activity against U.S. clinical isolates and organisms with challenging resistance phenotypes
Prevalence and antimicrobial susceptibilities of bacteria isolated from blood cultures of hospitalized patients in the United States in 2002
BACKGROUND: Bloodstream infections are associated with significant patient morbidity and mortality. Antimicrobial susceptibility patterns should guide the choice of empiric antimicrobial regimens for patients with bacteremia. METHODS: From January to December of 2002, 82,569 bacterial blood culture isolates were reported to The Surveillance Network (TSN) Database-USA by 268 laboratories. Susceptibility to relevant antibiotic compounds was analyzed using National Committee for Clinical Laboratory Standards guidelines. RESULTS: Coagulase-negative staphylococci (42.0%), Staphylococcus aureus (16.5%), Enterococcus faecalis (8.3%), Escherichia coli (7.2%), Klebsiella pneumoniae (3.6%), and Enterococcus faecium (3.5%) were the most frequently isolated bacteria from blood cultures, collectively accounting for >80% of isolates. In vitro susceptibility to expanded-spectrum β-lactams such as ceftriaxone were high for oxacillin-susceptible coagulase-negative staphylococci (98.7%), oxacillin-susceptible S. aureus (99.8%), E. coli (97.3%), K. pneumoniae (93.3%), and Streptococcus pneumoniae (97.2%). Susceptibilities to fluoroquinolones were variable for K. pneumoniae (90.3–91.4%), E. coli (86.0–86.7%), oxacillin-susceptible S. aureus (84.0–89.4%), oxacillin-susceptible coagulase-negative staphylococci (72.7–82.7%), E. faecalis (52.1%), and E. faecium (11.3%). Combinations of antimicrobials are often prescribed as empiric therapy for bacteremia. Susceptibilities of all blood culture isolates to one or both agents in combinations of ceftriaxone, ceftazdime, cefepime, piperacillin-tazobactam or ciprofloxacin plus gentamicin were consistent (range, 74.8–76.3%) but lower than similar β-lactam or ciprofloxacin combinations with vancomycin (range, 93.5–96.6%). CONCLUSION: Ongoing surveillance for antimicrobial susceptibility remains essential, and will enhance efforts to identify resistance and attempt to limit its spread
Prevalence of antimicrobial resistance in bacteria isolated from central nervous system specimens as reported by U.S. hospital laboratories from 2000 to 2002
BACKGROUND: Bacterial infections of the central nervous system, especially acute infections such as bacterial meningitis require immediate, invariably empiric antibiotic therapy. The widespread emergence of resistance among bacterial species is a cause for concern. Current antibacterial susceptibility data among central nervous system (CNS) pathogens is important to define current prevalence of resistance. METHODS: Antimicrobial susceptibility of pathogens isolated from CNS specimens was analyzed using The Surveillance Database (TSN(®)) USA Database which gathers routine antibiotic susceptibility data from >300 US hospital laboratories. A total of 6029 organisms derived from CNS specimen sources during 2000–2002, were isolated and susceptibility tested. RESULTS: Staphylococcus aureus (23.7%) and Streptococcus pneumoniae (11.0%) were the most common gram-positive pathogens. Gram-negative species comprised approximately 25% of isolates. The modal patient age was 1 or <1 year for most organisms. Prevalence of MRSA among S. aureus from cerebrospinal fluid (CSF) and brain abscesses were 29.9–32.9%. Penicillin resistance rates were 16.6% for S. pneumoniae, 5.3% for viridans group streptococci, and 0% for S. agalactiae. For CSF isolates, ceftriaxone resistance was S. pneumoniae (3.5%), E. coli (0.6%), Klebsiella pneumoniae (2.8%), Serratia marcescens (5.6%), Enterobacter cloacae (25.0%), Haemophilus influenzae (0%). Listeria monocytogenes and N. meningitidis are not routinely susceptibility tested. CONCLUSIONS: Resistance is commonly detected, albeit still at relatively low levels for key drugs classes such as third-generation cephalosporins. This data demonstrates the need to consider predominant resistance phenotypes when choosing empiric therapies to treat CNS infections
Sensing low concentrations of CO using flame-spray-made Pt/SnO2 nanoparticles
Tin dioxide nanoparticles of different sizes and platinum doping contents were synthesized in one step using the flame spray pyrolysis (FSP) technique. The particles were used to fabricate semiconducting gas sensors for low level CO detection, i.e. with a CO gas concentration as low as 5ppm in the absence and presence of water. Post treatment of the SnO2 nanoparticles was not needed enabling the investigation of the metal oxide particle size effect. Gas sensors based on tin dioxide with a primary particle size of 10nm showed signals one order of magnitude higher than the ones corresponding to the primary particle size of 330nm. In situ platinum functionalization of the SnO2 during FSP synthesis resulted in higher sensor responses for the 0.2wt% Pt-content than for the 2.0wt% Pt. The effect is mainly attributed to catalytic consumption of CO and to the associated reduced sensor response. Pure and functionalized tin dioxide nanoparticles have been characterized by Brunauer, Emmett and Teller (BET) surface area determination, X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy (STEM) while the platinum oxidation state and dispersion have been investigated by X-ray photoelectron spectroscopy (XPS) and extended X-ray absorption fine structure (EXAFS). The sensors showed high stability (up to 20days) and are suitable for low level CO detection: <10ppm according to European and 50ppm according to US legislation, respectivel
Ceramic matrix composite turbine engine vane
A vane has an airfoil shell and a spar within the shell. The vane has an outboard shroud at an outboard end of the shell and an inboard platform at an inboard end of the shell. The spar has a first chamber essentially along the suction side and a second chamber along the pressure side opposite the first chamber
Emerging resistance among bacterial pathogens in the intensive care unit – a European and North American Surveillance study (2000–2002)
Background Globally ICUs are encountering emergence and spread of antibiotic-resistant pathogens and for some pathogens there are few therapeutic options available.
Methods Antibiotic in vitro susceptibility data of predominant ICU pathogens during 2000–2 were analyzed using data from The Surveillance Network (TSN) Databases in Europe (France, Germany and Italy), Canada, and the United States (US).
Results Oxacillin resistance rates among Staphylococcus aureus isolates ranged from 19.7% to 59.4%. Penicillin resistance rates among Streptococcus pneumoniae varied from 2.0% in Germany to as high as 20.2% in the US; however, ceftriaxone resistance rates were comparably lower, ranging from 0% in Germany to 3.4% in Italy. Vancomycin resistance rates among Enterococcus faecalis were ≤ 4.5%; however, among Enterococcus faecium vancomycin resistance rates were more frequent ranging from 0.8% in France to 76.3% in the United States. Putative rates of extended-spectrum β-lactamase (ESBL) production among Enterobacteriaceae were low, \u3c6% among Escherichia coli in the five countries studied. Ceftriaxone resistance rates were generally lower than or similar to piperacillin-tazobactam for most of the Enterobacteriaceae species examined. Fluoroquinolone resistance rates were generally higher for E. coli (6.5% – 13.9%), Proteus mirabilis (0–34.7%), and Morganella morganii (1.6–20.7%) than other Enterobacteriaceae spp (1.5–21.3%). P. aeruginosa demonstrated marked variation in β-lactam resistance rates among countries. Imipenem was the most active compound tested against Acinetobacter spp., based on resistance rates.
Conclusion There was a wide distribution in resistance patterns among the five countries. Compared with other countries, Italy showed the highest resistance rates to all the organisms with the exception of Enterococcus spp., which were highest in the US. This data highlights the differences in resistance encountered in intensive care units in Europe and North America and the need to determine current local resistance patterns by which to guide empiric antimicrobial therapy for intensive care infections
Tracking the implementation of NCCLS M100-S12 expanded-spectrum cephalosporin MIC breakpoints for nonmeningeal isolates of Streptococcus pneumoniae by clinical laboratories in the United States during 2002 and 2003
BACKGROUND: The Performance Standards for Antimicrobial Susceptibility Testing, Twelfth Informational Supplement, M100-S12, published by the National Committee for Clinical Laboratory Standards (NCCLS) in January 2002 introduced distinct minimum inhibitory concentration (MIC) interpretative breakpoints for ceftriaxone, cefotaxime, and cefepime for nonmeningeal isolates of Streptococcus pneumoniae. Previously, a single set of interpretative breakpoints was used for both meningeal and nonmeningeal isolates. METHODS: To estimate the rate of adoption of the M100-S12 interpretive breakpoints by clinical laboratories, antimicrobial susceptibility test results for ceftriaxone and cefotaxime from nonmeningeal S. pneumoniae isolates were studied using data collected from January 2002 to June 2003 by The Surveillance Network(® )Database – USA (TSN(®)), an electronic surveillance database. RESULTS: Of the 262 laboratories that provided data that could be evaluated, 67.6% had adopted the M100-S12 breakpoints one and one-half years after they were published. CONCLUSIONS: The NCCLS M100-S12 recommendation to interpret MICs to expanded-spectrum cephalosporins using two distinct sets of breakpoints for meningeal and nonmeningeal isolates of S. pneumoniae was steadily implemented by clinical microbiology laboratories in the United States following their initial publication in January 2002. The use of these new breakpoints more accurately reflects the clinical activities of expanded-spectrum cephalosporins than did the single set of interpretative breakpoints previously used for both meningeal and nonmeningeal isolates
A data mining approach to the SAR values over large MR image repositories
Purpose: In magnetic resonance imaging, the radiofrequency energy
absorption arises as one of the main safety concerns, being mainly related with
increased body temperature. Monitoring radiofrequency absorption is achieved
by the estimation of specific absorption rate (SAR), whose implementation lies
on equipment manufacturers, which in turn are not totally enlightening about its
calculus. This work presents an exploratory approach of whole-body SAR
values stored in DICOM metadata aiming to find correlation with body weight,
body mass index (BMI), gender and pulse sequences for abdominal/pelvic
(17.812 series) and head (29.907 series) studies.
Methods and Materials: All studies were acquired in a 3 Tesla scanner with
high-performance gradients. Data were extracted using Dicoogle, a DICOM
metadata mining tool. Several DICOM tags were analysed (e.g. patient weight,
height, gender, sequence name). For each study type, specifically weighted
pulse sequences were related with weight, BMI and gender through boxplot
diagrams, statistical and effect size analysis.
Results: SAR limits were never exceeded. Generally, SAR values tended to
decrease with increasing body weight and BMI values for abdominal/pelvic
studies. On the other hand, head studies showed different trends regarding
distinct pulse sequences. SAR values tend to be higher in male individuals
(p<0,05). As expected, turbo spin echo sequences present the highest SAR
values. The values found for echo gradient spoiled sequence (FLASH) were
also high.
Conclusion: It is confirmed that SAR estimates are related with the analysed
variables. An individual examination of pulse sequences is recommended to
observe trends regarding weight, BMI or gender.publishe
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