Search

Background The epidemiology of nosocomial bloodstream infections (NBSIs) in patients with coronavirus disease 2019 (COVID-19) is poorly understood, due in part to substantial disease heterogeneity resulting from multiple potential pathogens. Methods We identified risk factors for NBSIs and examined the association between NBSIs and mortality in a retrospective cohort of patients hospitalized with COVID-19 in 2 New York City hospitals during the height of the pandemic. We adjusted for the potential effects of factors likely to confound that association, including age, race, illness severity upon admission, and underlying health status. Results Between January 1 and October 1, 2020, 1403 patients had a positive blood culture, and 79 and 101 met the stringent criteria for NBSI among non-COVID-19 and COVID-19 patients, respectively. NBSIs occurred almost exclusively among patients who were severely ill with COVID-19 at hospital admission. NBSIs were associated with elevated mortality, even after adjusting for baseline differences in COVID-19 illness (55% cases vs 45% controls; P = .13). Mortality was concentrated in patients with early-onset pneumonia caused by S. aureus and gram-negative bacteria. Less virulent Candida (49%) and Enterococcus (12%) species were the predominant cause of NBSI in the latter stages of hospitalization, after antibiotic treatment and COVID-19 treatments that attenuate immune response. Most Enterococcus and Candida infections did not have an identifiable source and were not associated with common risk factors for infection by these organisms. Conclusions Pathogen species and mortality exhibited temporal differences. Early recognition of risk factors among COVID-19 patients could potentially decrease NBSI-associated mortality through early COVID-19 and antimicrobial treatment.

We revisit the representation theory of the quantum double of the universal cover of the Lorentz group in 2+1 dimensions, motivated by its role as a deformed Poincar\'e symmetry and symmetry algebra in (2+1)-dimensional quantum gravity. We express the unitary irreducible representations in terms of covariant, infinite-component fields on curved momentum space satisfying algebraic spin and mass constraints. Adapting and applying the method of group Fourier transforms, we obtain covariant fields on (2+1)-dimensional Minkowski space which necessarily depend on an additional internal and circular dimension. The momentum space constraints turn into differential or exponentiated differential operators, and the group Fourier transform induces a star product on Minkowski space and the internal space which is essentially a version of Rieffel's deformation quantisation via convolution., Comment: 36 pages, 2 figures; minor corrections and additional references (version to appear in Letters in Mathematical Physics)

The recent emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has posed formidable challenges for clinical laboratories seeking reliable laboratory diagnostic confirmation. The swift advance of the crisis in the United States has led to Emergency Use Authorization (EUA) facilitating the availability of molecular diagnostic assays without the more rigorous examination to which tests are normally subjected prior to FDA approval. Our laboratory currently uses two real-time reverse transcription-PCR (RT-PCR) platforms, the Roche Cobas SARS-CoV2 and the Cepheid Xpert Xpress SARS-CoV-2., The recent emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has posed formidable challenges for clinical laboratories seeking reliable laboratory diagnostic confirmation. The swift advance of the crisis in the United States has led to Emergency Use Authorization (EUA) facilitating the availability of molecular diagnostic assays without the more rigorous examination to which tests are normally subjected prior to FDA approval. Our laboratory currently uses two real-time reverse transcription-PCR (RT-PCR) platforms, the Roche Cobas SARS-CoV2 and the Cepheid Xpert Xpress SARS-CoV-2. The two platforms demonstrate comparable performances; however, the run times for each assay are 3.5 h and 45 min, respectively. In search for a platform with a shorter turnaround time, we sought to evaluate the recently released Abbott ID Now COVID-19 assay, which is capable of producing positive results in as little as 5 min. We present here the results of comparisons between Abbott ID Now COVID-19 and Cepheid Xpert Xpress SARS-CoV-2 using nasopharyngeal swabs transported in viral transport media and comparisons between Abbott ID Now COVID-19 and Cepheid Xpert Xpress SARS-CoV-2 using nasopharyngeal swabs transported in viral transport media for Cepheid and dry nasal swabs for Abbott ID Now. Regardless of method of collection and sample type, Abbott ID Now COVID-19 had negative results in a third of the samples that tested positive by Cepheid Xpert Xpress when using nasopharyngeal swabs in viral transport media and 45% when using dry nasal swabs.

RationaleThe Infectious Diseases Society of America has identified the use of SARS-CoV-2 genomic load for prognostication purposes as a key research question.ObjectivesWe explored the SARS-CoV-2 genomic load as a risk factor for adverse patient outcomes.MethodsA retrospective cohort study among adult patients admitted to the hospital between March 31st to April 10th, 2020 with COVID-19 pneumonia was conducted. We segregated patients into 3 genomic load groups: low (Cycle threshold (Ct) ≥35), intermediate (25MeasurementsA composite outcome of death, intubation, and/or extracorporeal membrane oxygenation was used. Secondary outcomes included the severity of pneumonia on admission, as measured by the Pneumonia Severity Index (PSI).Main ResultsOf 457 patients with COVID-19 pneumonia from March 31st to April 10th, 2020, 316 met inclusion criteria. Included patients were followed for a median of 25days (IQR 21-28). High genomic load at presentation was associated with higher Charlson Comorbidity Index (p=0.005), transplant recipient status (pConclusionsOur findings suggest that a high genomic load of SARS-CoV-2 at the time of admission is an independent predictor of adverse outcomes, that above and beyond age, comorbidity, and severity of illness on presentation, may be used to risk-stratify patients, and call for a quantitative diagnostic assay to become available.

The recent emergence of the SARS-CoV-2 pandemic has posed formidable challenges for clinical laboratories seeking reliable laboratory diagnostic confirmation. The swift advance of the crisis in the United States has led to Emergency Use Authorization (EUA) facilitating the availability of molecular diagnostic assays without the more rigorous examination to which tests are normally subjected prior to FDA approval. Our laboratory currently uses two real time RT-PCR platforms, the Roche Cobas SARS-CoV2 and the Cepheid Xpert Xpress SARS-CoV-2. Both platforms demonstrate comparable performance; however, the run times for each assay are 3.5 hours and 45 minutes, respectively. In search for a platform with shorter turnaround time, we sought to evaluate the recently released Abbott ID NOW COVID-19 assay which is capable of producing positive results in as little as 5 minutes. We present here the results of comparisons between Abbott ID NOW COVID-19 and Cepheid Xpert Xpress SARS-CoV-2 using nasopharyngeal swabs transported in viral transport media and comparisons between Abbott ID NOW COVID-19 and Cepheid Xpert Xpress SARS-CoV-2 using nasopharyngeal swabs transported in viral transport media for Cepheid and dry nasal swabs for Abbott ID NOW. Regardless of method of collection and sample type, Abbott ID NOW COVID-19 had negative results in a third of the samples that tested positive by Cepheid Xpert Xpress when using nasopharyngeal swabs in viral transport media and 45% when using dry nasal swabs.

Background The timely identification of a cluster is a critical requirement for infection prevention and control (IPC) departments because these events may represent transmission of pathogens within the health care setting. Given the issues with manual review of hospital infections, a surveillance system to detect clusters in health care settings must use automated data capture, validated statistical methods, and include all significant pathogens, antimicrobial susceptibility patterns, patient care locations, and health care teams. Methods We describe the use of SaTScan statistical software to identify clusters, WHONET software to manage microbiology laboratory data, and electronic health record data to create a comprehensive outbreak detection system in our hospital. We also evaluated the system using the Centers for Disease Control and Prevention's guidelines. Results During an 8-month surveillance time period, 168 clusters were detected, 45 of which met criteria for investigation, and 6 were considered transmission events. The system was felt to be flexible, timely, accepted by the department and hospital, useful, and sensitive, but it required significant resources and has a low positive predictive value. Conclusions WHONET-SaTScan is a useful addition to a robust IPC program. Although the resources required were significant, this prospective, real-time cluster detection surveillance system represents an improvement over historical methods. We detected several episodes of transmission which would have eluded us previously, and allowed us to focus infection prevention efforts and improve patient safety.

Background Pneumonia is a leading cause of hospitalization and mortality. Due to the low yield of available diagnostic tests, ATS/IDSA pneumonia guidelines recommend a microbiologic work-up only for hospitalized patients with severe pneumonia. Methods From 5/2019 to 1/2020, we selected adult patients with clinical and radiographic findings highly suggestive of pneumonia. The BioFire® FilmArray® pneumonia panel was performed on sputum specimens that met quality microbiologic criteria and the results were compared to those of sputum cultures and other tests sent per standard of care. A limit of 105 copies/mL was used for positivity in semi-quantitative bacterial targets. The empiric antimicrobial regimen was reviewed to quantify the potential for antimicrobial optimization. Results Seventy patients were included in the analysis. Median age was 70 (IQR 53.5–81.75), and the majority (43 patients, 61.4%) were classified as Class IV and V using the pneumonia severity index, indicating severe cases of pneumonia. Sixty-nine patients completed at least a 5-day course for pneumonia and 14.3% died during their hospitalization. The fifteen patients (21.4%) that submitted a sputum culture before the initiation of antimicrobial therapy, had a trend towards a positive sputum culture (60% (9/15) vs 36.4% (20/55)) (p=0.09). The BioFire® FilmArray® pneumonia Panel increased the number of patients who received a microbiologic diagnosis from 29 (41%) to 59 (84.3%) (p< 0.001). The per isolate analysis revealed significantly more targets detected for Haemophilus influenzae (p=0.002) and Streptococcus pneumoniae (p=0.05). On review of empiric antimicrobial treatment, there was possibility for antimicrobial optimization in 80% of patients, including 9 cases of pathogens (4 MRSA, 3 Legionella pneumophila, 2 CTX-M gram-negative rods) where the pathogens were not covered and another 70 antimicrobials in 49 patients that could be stopped. Flow chart Bacterial Pathogens Detected in Standard of Care Alone Testing and with the Addition of Pneumonia Panel. Potential for Antimicrobial Optimization Using the Pneumonia Panel Conclusion Incorporation of the pneumonia panel in the diagnostic work-up of patients hospitalized with pneumonia substantially increased the rate of microbiologic diagnosis and had the potential to guide appropriate antimicrobial therapy. Future studies to quantify the effects on clinical outcomes and cost-effectiveness from tailored therapy are needed. Disclosures All Authors: No reported disclosures

Cryptococcosis is infrequent in children, and isolated cryptococcal osteomyelitis is rarely encountered. Here, we describe a 14-year-old patient in remission from T-cell acute lymphoblastic leukemia with osteomyelitis because of Cryptococcus neoformans var. grubii. The patient was effectively treated with antifungal therapy.

The release of organic compounds from roots is a key process influencing soil carbon (C) dynamics and nutrient availability in terrestrial ecosystems. Through this process, plants stimulate microbial activity and soil organic matter (SOM) mineralization thus releasing nitrogen (N) that sustains gross and net primary production (GPP and NPP, respectively). Root inputs also contribute to SOM formation. In this study, we quantified the annual net root-derived C input to soil (Net-Croot) across six high fertility forests using an in-growth core isotope technique. On the basis of Net-Croot, wood and coarse root biomass changes, and eddy covariance data, we quantified net belowground C sequestration. Belowground C accumulation and GPP were inversely related to soil C:N, but not to climate or stand age. Soil C content and C:N were also related to soil texture. At these high fertility sites, biomass growth did not change with soil C:N; however, biomass growth-to-GPP ratio significantly increased with increasing soil C:N. This was true for both our six forest sites and for another 23 high fertility sites selected at a global scale. We suggest that, at high fertility sites, plant N demand interacts with soil C:N stoichiometry and microbial activity, resulting in higher allocation of C to above ground tree biomass with increasing soil C:N ratio. When C:N is high, microbes have a low C use efficiency, respire more of the fresh C inputs by roots and prime SOM decomposition, thereby increasing N availability for tree uptake. Soil C sequestration would therefore decrease, whereas the extra N released during SOM decomposition can promote tree growth and ecosystem C sink allocation in aboveground biomass. Conversely, C is sequestered in soil when low soil C:N promotes microbial C use efficiency and new SOM formation and stabilization on clay particles.

The energy spectra of the γ-rays emitted in the 35Cl + 92Mo reaction at incident energy E = 260 MeV were measured in coincidence with the ejectiles produced in dissipative reaction events. The cumulative energy spectrum of the γ-rays coming from the decay of the ejectiles was calculated within the statistical model and its comparison to the experimental spectrum evidences an excess in the data for Eγ = 8 to 12 MeV. Such an excess, fitted with a Lorentz curve, is attributed to the preequilibrium GDR γ-decay of the intermediate dinuclear system. The centroid energy of the Lorentz curve corresponds to a dipole oscillation along the symmetry axis of the system and its width is found to be comparable to that of the ground state GDR low energy component of the deformed dinucleus. The small quantal dispersion Δl = (10.3 ± 0.1)ħ of the entrance channel angular momentum, determined by analysing the dissipative fragment angular distribution in the framework of the Strutinsky model, is suggested to limit the broadening of the preequilibrium GDR width.

The reaction dynamics induced by the 17F Radioactive Ion Beam on the proton-shell closed 58Ni target was studied at two colliding energies slightly above the Coulomb barrier. Charged reaction products were detected at forward angles and the quasi-elastic differential cross section was analyzed within the framework of the optical model in order to extract the reaction cross section and to investigate the relevance of direct reaction channels (inelastic scattering, breakup and transfer) at near-barrier energies. The comparison with the reaction induced by double-magic tightly-bound 16O projectiles on the same target showed that the 17F reaction cross section is moderately enhanced at the lower secondary beam energy. Direct reaction channels were also found to be more relevant than for the corresponding 16O-induced reaction.

The excitation of the dynamical dipole mode along the fusion path was investigated for the first time in the formation of a heavy compound nucleus in the $A\ensuremath{\sim}190$ mass region. The compound nucleus was formed at identical conditions of excitation energy and spin from two entrance channels: the charge-asymmetric $^{40}\mathrm{Ca}+^{152}\mathrm{Sm}$ and the nearly charge-symmetric $^{48}\mathrm{Ca}+^{144}\mathrm{Sm}$ at ${E}_{\text{lab}}=11$ and 10.1 MeV/nucleon, respectively. High-energy $\ensuremath{\gamma}$ rays and light charged particles were measured in coincidence with evaporation residues by means of the MEDEA multidetector array (Laboratori Nazionali del Sud, Italy) coupled to four parallel plate avalanche counters. The charged particle multiplicity spectra and angular distributions were used to pin down the average excitation energy, the average mass, and the average charge of the compound nucleus. The $\ensuremath{\gamma}$-ray multiplicity spectrum and angular distribution related to the nearly charge-symmetric channel were employed to obtain new data on the giant dipole resonance in the compound nucleus. The dynamical dipole mode excitation in the charge-asymmetric channel was evidenced, in a model-independent way, by comparing the $\ensuremath{\gamma}$-ray multiplicity spectra and angular distributions of the two entrance channels with each other. Calculations of the dynamical dipole mode in the $^{40}\mathrm{Ca}+^{152}\mathrm{Sm}$ channel, based on a collective bremsstrahlung analysis of the reaction dynamics, are presented. Possible interesting implications in the superheavy-element quest are discussed.

Will Mediterranean terrestrial ecosystems be affected by the expected changes in precipitation regimes? If so, by how much and in which direction? These questions are at the basis of the research performed in context of the EU MIND project, whose key objectives were: i) to investigate the potential effects of increasing drought on Mediterranean terrestrial ecosystems at the process, ecosystem and regional scales and ii) to assess ecosystem vulnerability to changes in rainfall patterns. A network of experimental study sites has been created in Portugal, Spain, France and Italy, where field manipulations alter the amount of water available to the ecosystem. The most up-to-date methods of ecophysiology, micrometeorology, soil ecology and remote sensing have been used to elucidate the mechanisms that regulate the response of vegetation and soil to changes in water availability. This information is providing the basis for the implementation and validation of simulation models capable of predicting the drought response of Mediterranean terrestrial ecosystems, and their vulnerability to future climate change, on a larger scale. The out-coming results are elucidating how water availability affects plant ecophysiological processes, the dynamics of soil carbon and the overall exchange of mass and energy between the land and the atmosphere. This paper focuses on some of the important, yet preliminary, results on C and energy fluxes that have been obtained at the large scale troughfall manipulation experiment (Tolfa, Italy), in a forest dominated by Arbutus unedo L.

Partitioning soil carbon dioxide (CO2) efflux (RS) into autotrophic (RA; including plant roots and closely associated organisms) and heterotrophic (RH) components has received considerable attention, as differential responses of these components to environmental change have profound implications for the soil and ecosystem C balance. The increasing number of partitioning studies allows a more detailed analysis of experimental constraints than was previously possible. We present results of an exhaustive literature search of partitioning studies and analyse global trends in flux partitioning between biomes and ecosystem types by means of a metaanalysis. Across all data, an overall decline in the RH/RS ratio for increasing annual RS fluxes emerged. For forest ecosystems, boreal coniferous sites showed significantly higher (Po0.05) RH/RS ratios than temperate sites, while both temperate or tropical deciduous forests did not differ in ratios from any of the other forest types. While chronosequence studies report consistent declines in the RH/RS ratio with age, no difference could be detected for different age groups in the global data set. Different methodologies showed generally good agreement if the range of RS under which they had been measured was considered, with the exception of studies estimating RH by means of root mass regressions against RS, which resulted in consistently lower RH/RS estimates out of all methods included. Additionally, the time step over which fluxes were partitioned did not affect RH/RS ratios consistently. To put results into context, we review the most common techniques and point out the likely sources of errors associated with them. In order to improve soil CO2 efflux partitioning in future experiments, we include methodological recommendations, and also highlight the potential interactions between soil components that may be overlooked as a consequence of the partitioning process itself.

A low threshold charged particle three-stage detector has been designed, built and successfully tested. A truncated pyramidal geometry has been chosen to use the device as an element in a large solid angle array for heavy ion nuclear experiments. Angular resolution of 0.4° at 35 cm from the target, energy resolution of about 1% for the elastically scattered ions and Z resolving power of 63 for Z = 17 have been achieved in the 35 Cl+ 64 Ni reaction at 280 MeV incident energy.

We have studied the elastic scattering of the exotic 17 F nuclei from 208 Pb at Coulomb barrier energies. For the measurement we used a new detector array with pixel structure and a large solid angle. Optical potential analysis shows that 17 F has an imaginary potential much less deep than 19 F. Information on the exclusive 17 F breakup cross section has been deduced too.

The heavy-ion magnetic spectrometer PRISMA was recently installed at Laboratori Naz. di Legnaro, in order to exploit the heavy-ion beams of the XTU Tandem-ALPI-PIAVE accelerator complex, with masses up to A≃200 at energies ≃5-10 MeV MeV A.

We studied the elastic scattering process for the system (17)F + (58)Ni at two colliding energies slightly above the Coulomb barrier. The experimental data were analyzed within the framework of the optical model to investigate the effects of the projectile small binding energy (S(p) = 600 keV) on the reaction dynamics. We found that in this energy range the "reduced" reaction cross section for the system (17)F + (58)Ni is rather similar to that induced by the interaction of tightly-bound (16)O nuclei on the same target. Nuclear Physics A

Background Antibiotic (ABX) use and outcome measures (rate of HO-CDI, local antimicrobial resistance) are recommended ASP metrics. These metrics can be used for internal benchmarking to assess ASP performance within an institution over time. Methods An adult ASP at our 750-bed academic medical center was implemented in 2008. ASP interventions include prospective audit and feedback, prior authorization with fluoroquinolone (FLQ) restriction as an ASP target and implementation of facility-specific guidelines for common infections. Newer ASP initiatives were Cepheid/Xpert for blood cultures with Gram-positive cocci in pairs and clusters with daily real-time ASP interventions (11/2014), oral vancomycin secondary prophylaxis for patients with prior CDI (4/2014) and optimization of β-lactam (BL) dosing (piperacillin-tazobactam [PTZ] extended infusion hospital-wide 4/2013; cefepime [CEF] 4/2015 and meropenem 7/2015 protocols). ABX use is measured in days of therapy per 1000 patient-days (DOT/1000 PD) and length of therapy/admission when ABX were administered (LOT/ADM). NHSN definition is used for HO-CDI. For resistance trends the first unique isolate/patient/year regardless of source or susceptibility profile was included. Statistical analysis of trends during 8-years period 2009–2016 was performed by Poisson (SAS). Results Major shifts in ABX use include decrease in FLQ use (-17%, P < 0.01) with compensatory increase in ceftriaxone (CTX, +12%, P < 0.01), antipseudomonal BL (+3%, P < 0.01) and no change in carbapenem (+0.6%, P=0.5) as well as an increase in nafcillin and oxacillin (+7%, P < 0.01) use. There was a decrease in aggregate LOT/ADM (-4%, P < 0.01) with no change in DOT/1000 PD. We observed a decrease in HO-CDI rate (-17%, P < 0.01). Major resistance trends include reduction in Enterobacteriaceae spp. and Pseudomonas aeruginosa isolates nonsusceptible (NS) to FLQ (-4%, P < 0.01; -10%, P < 0.01, respectively) with increase in Enterobacteriaceae spp. NS to ceftriaxone, (+3%, P < 0.01). A decrease in P. aeruginosa NS to PTZ (-11%, P < 0.01) and no change for CEF was reported. There was no difference in Enterobacteriaceae spp. NS to PTZ or CEF. Conclusion Overall, reported trends aligned with ASP initiatives. Increased CTX NS is of concern and warrants an ASP-led strategy to decrease CTX use. Disclosures All authors: No reported disclosures.

A new facility, named EXOTIC, for the in‐flight production of light low‐energy weakly bound Radioactive Ion Beams (RIBs) is now fully operational at the Laboratori Nazionali di Legnaro (LNL) of the INFN. In this contribution we will present the facility, the Monte‐Carlo code we developed to properly describe the reaction dynamics inside the production target, the experimental results achieved and a list of possible RIBs delivered from the facility EXOTIC in the next future.

An estimated 290,000 surgical site infections occur after a procedure in the United States annually, accounting for 22% of all healthcare associated infections [1]. Deep surgical site infections (SSI) after arthroplasty or spine fusion surgery complicate up to 2% of cases, and result in revision surgery and prolonged antibiotic use [2, 3]. The patient morbidity and healthcare system cost is tremendous, with an estimated $566 million spent annually in hospital treatment costs for arthroplasty SSI alone [4]. Staphylococcus aureus is a frequent and feared cause of these infections, given its unique pathogenicity and ability to adhere to prosthetic material [5, 6]. Studies indicate S. aureus colonization prior to surgery is a risk of subsequent infection, with the nasal mucosa serving as a reservoir for S. aureus colonization and a source of secondary transmission to other body sites [7, 8]. Prevention of SSI by treatment of S. aureus colonization with intranasal topical mupirocin has been studied. A short-term suppression rate of 83% after multiple doses of nasal mupirocin was achieved in one randomized, placebo-controlled trial of 891 S. aureus colonized patients, resulting in a statistically significant reduction of invasive S. aureus infection [9]. Several controlled trials suggest a reduction in SSI with the use of pre-operative topical antiseptics [10, 11]. When nasal mupirocin was combined with use of chlorhexidine soap in a randomized, double-blind, placebo-controlled trial including 808 S. aureus colonized surgical patients, a significant reduction in deep S. aureus SSI was realized [12]. To reduce the risk of SSI after arthroplasty and spine fusion surgery at our institution, we historically provided a prescription for brand mupirocin ointment specifically formulated for application on intranasal mucosal surfaces twice a day for the five days prior to surgery, and instructions for the use of chlorhexidine soap the evening before surgery. After implementation of this protocol, we conducted an anonymous patient survey to measure compliance. Although 94% of patients used the chlorhexidine soap, only 86% applied the mupirocin ointment and 8% of patients stated they found it hard or very hard to purchase the mupirocin due to cost [13]. The brand nasal mupirocin ointment specifically produced for application on intranasal mucosal surfaces is only formulation currently available; although generic mupirocin ointment for topical use on skin is available at less cost, application of this formulation on mucosal surfaces may cause irritation. Our survey results, plus reports of emerging mupirocin resistance, led us to search for alternatives [14–19]. Povidone-iodine solution is a broad-spectrum antiseptic suitable for suppression of S. aureus in nasal secretions [20]. In contrast to the application of nasal mupirocin antibiotic ointment to eradicate S. aureus in the nares before surgery, the application of povidone iodine is intended to transiently suppress S. aureus in the nares during surgery. Our hypothesis was a one-time application of nasal povidone iodine just prior to surgery would be as effective as twice daily applications of nasal mupirocin during the five days before surgery in preventing SSI, and provide a more convenient option for patients at lower cost.

A new system for soil respiration measurement [P. Rochette, L.B. Flanagan, E.G. Gregorich. Separating soil respiration into plant and soil components using analyses of the natural abundance of carbon-13. Soil Sci. Soc. Am. J., 63, 1207-1213 (1999).] was modified in order to collect soil-derived CO2 for stable isotope analysis. The aim of this study was to assess the suitability of this modified soil respiration system to determine the isotopic composition (δ13C) of soil CO2 efflux and to measure, at the same time, the soil CO2 efflux rate, with the further advantage of collecting only one air sample. A comparison between different methods of air collection from the soil was carried out in a laboratory experiment. Our system, as well as the other dynamic chamber approach tested, appeared to sample the soil CO2, which is enriched with respect to the soil CO2 efflux, probably because of a mass dependent fractionation during diffusion and because of the atmospheric contribution in the upper soil layer. On the contrary, the static accumulation of CO2 into the chamber headspace allows sampling of δ13C-CO2 of soil CO2 efflux. © 2006 Taylor & Francis.

Recent data on inclusive and exclusive breakup and on fusion at Coulomb barrier energies are presented and comparatively discussed for the systems 6Li,17F+208Pb. Both projectiles are very loosely bound and moreover 17F is an unstable beam. The breakup strength in 6Li, bound by 1.47 MeV, is one order of magnitude larger than in 17F, bound by 0.60 MeV; this is at contrary to simple expectations and suggests that other effects, maybe connected to the specific structure of the nuclei (e.g. 6Li cluster structure ?), in addition to the binding energies, influence the breakup process.

The low intensity (about 105-106 pps) of the presently available RNBs (Radioactive Nuclear Beams) requires detection apparatuses with large solid angle coverage and high granularity. Moreover, the utilization of highly segmented detectors needs unconventional read-out systems appositely designed and the development of electronic boards making use of highly miniaturized and integrated circuitry (ASIC chip). The EXODET (EXOtic DETector) apparatus has been designed and constructed following these guide lines. It consists of large-area silicon detectors segmented in 100 strips on a single side. The particle energy loss information is obtained from the unsegmented side using standard electronic chains, while for the read-out of the incident position information we found suitable a chip already developed for high-energy particle physics experiments. EXODET has been already successfully used in exotic nuclei experiments devoted to the study of the scattering of 17F on a 208Pb target and of 11Be on a 209Bi target at energies around the Coulomb barrier, performed at the Argonne National Laboratory (USA) and at the RIKEN Laboratory (Japan), respectively. The development of these modern and compact detection systems opens new and interesting perspectives for experimentation with RNBs.

Intermediate mass fragments (IMF) and light particles emitted from the Ni-58 + Ni-58 reaction at a beam energy of 375 MeV have been studied. The fragments and light particles were measured in coincidence with 4 pi gamma-ray spectrometer. The Z=6 (C) kinetic energy spectra and the distribution of the final nuclei in coincidence with the emitted C are well described by Hauser-Feshbach calculations extended to many channels. A detailed study of C-Psi and 3 alpha-gamma correlations indicate a strong selectivity of the IMF decay. Our results indicate that the IMF can populate nuclei that are not accessible via multiple light particle (Z

A new detector apparatus has been designed and developed to be used in experiments performed with radioactive ion beams. It consists of 16 highly segmented silicon strip detectors arranged in two‐layer telescopes and subtending a large solid angle (about 70% of 4π sr). An innovative readout system for the position information that uses highly integrated electronics (ASIC chips) has been implemented. A first successful experiment has been performed at the Argonne National Laboratory (USA) to study the 17F scattering by a 208Pb target at 90.4 MeV of incident energy. The 17F angular distribution has been analyzed and the optical model potential best‐fit parameters determined. The same analysis performed on 17F data taken at higher incident energy, in completely different experimental conditions, gives consistent results. The comparison with experiments performed with stable beams (19F, 16O, 17O) indicates a behavior for the 17F more similar to that of the Oxygen isotopes than to the 19F one. Despite of the short data collection time, also the cross section for the 17F →16O + p break‐up process has been estimated.

Bartonella henselae was isolated from the blood of five febrile immunosuppressed patients using BacT/Alert (Organon Teknika, Durham, NC) automated microbial detection system. An immunofluorescence assay (using 1:1000 dilutions) was used to confirm identification of fastidious, pleomorphic, non-Gram staining, argyrophilic bacilli displaying rachety motility that had been presumptively identified as Bartonella spp. The practicality of identification of Bartonella henselae using goat antisera for use in a routine clinical microbiology laboratory was demonstrated by this study.

The properties of the strong fluctuations observed in the excitation functions of Dissipative Binary Heavy Ion Collisions (DBHIC) have been studied for the system28Si+28Si in the energy range 150 MeV ≤Elab ≤ 156 MeV with 150 keV step laboratory incident energy, by angular distributions and excitation functions measurements. Experimental results are compared to the the recently developed Partially Overlapping Molecular Level Model (POMLM). The parameters of the model have been determined with reasonable accuracy by describing all the quantities characterizing the fluctuations in the excitation functions i.e.: Average Angular Distributions, Energy Autocorrelation Functions, Variances, Angular Correlation Coefficients. The results of the analysis strongly support the idea of a process proceeding through the formation of an highly excited “nuclear molecule”. Experimental data collected at the most forward angles show the effects of strong excitation of a few final channels.

The yield of γ-rays emitted in the dissipative reaction 19F + 12C, at Elab = 121.7 MeV has been measured in coincidence with α-particles emitted at θlab = 10°. Comparison with preliminary statistical model calculations shows that assuming only compound nucleaus formation is not sufficient to reproduce the data. Other mechanisms have to be included before information on reaction dynamics can be extracted and definitive conclusions can be drawn.

We describe 2 patients without prior exposure to linezolid who were infected with closely related strains of linezolid- and vancomycin-resistant Enterococcus faecium (LRVREF) that may have been hospital acquired. Polymerase chain reaction amplification of the domain V region of the 23S ribosomal RNA gene demonstrated the presence of the G2576U mutation previously reported to be associated with linezolid resistance. Nosocomial transmission of LRVREF is an ominous sign and underscores the importance of meticulous infection-control measures.

A. Pakou1, N. Patronis1, D. Pierroutsakou2, A.M. Sanchez-Benitez3, L. Acosta3,4, N. Alamanos5, A. Boiano2, G. Inglima6, D. Filipescu7, T. Glodariu7, A. Guglielmetti8, M. La Commara6, G. Lalazissis9, I. Martel3, C. Mazzocchi8, M. Mazzocco10, P. Molini10, C. Parascandolo2, M. Sandoli6, C. Signorini10, R. Silvestri6, F. Soramel10, M. Romoli2, E. Stiliaris11, A. Trzcinska12, K. Zerva1, E. Vardaci6, A. Vitturi10.

Non-statistical gamma rays of energy ranging in the interval from 5 MeV to 12 MeV are found to be emitted in coincidence with projectile-like fragments from the quasi-elastic 28 Si + 64 Ni reaction measured at E lab = 143 MeV. Boltzmann-Nordheim- Vlasov calculations are consistent with the hypothesis that they are originated from surface oscillations, of quadrupole or higher multipolarity, of the two colliding nuclei.

Invited talk

Charged reaction products originated from the interaction of the loosely bound radioactive ion beam {sup 17}F (S{sub p}=600 keV) with the proton-shell closed {sup 58}Ni target were measured at two colliding energies slightly above the Coulomb barrier. The collected data were analyzed within the framework of the optical model to deduce the reaction cross section and to investigate the role played by inelastic excitations, transfer channels, and the breakup process {sup 17}F{yields}{sup 16}O+p at near-barrier energies. The reaction cross section at the lower {sup 17}F energy showed a moderate enhancement ({approx}20%) with respect to that of the system {sup 16}O+{sup 58}Ni. At this energy direct reaction channels were also found to be more relevant than those for the reaction induced from the tightly bound projectile {sup 16}O on the same target. Both features could be strongly related to the very low binding energy of the {sup 17}F valence proton.

Coherence energies extracted from excitation functions and angular distributions for the fragments emitted in the19F+63Cu reaction, measured in the range θlab=10° to 120° at incident energies between 100 to 108 MeV (lab.), were compared to the Kun model of dissipative collisions. An overall agreement was found for the angular distributions at forward angles. The general behavior of coherence energies was also properly described and interaction times were deduced.

A coincidence experiment was performed on the24Mg(16O,12Cα) reaction at an incident energy of 84.6 MeV. The measured relative energy spectra show the excitation of16O selected states decaying into the α-12C channel.

Elastic scattering angular distributions of $^{32,36}\mathrm{S}$ (beams)${+}^{58.64}$Ni have been measured at several energies around the Coulomb barrier. An optical-model analysis of the data reveals remarkable energy dependences of the potentials at the strong absorption radii, in all cases. The largest effects are observed for $^{32}\mathrm{r}$/rS${+}^{64}$Ni. This is due to the coupled reaction channels which also strongly influence the sub-barrier fusion cross sections. Coupled-channels calculations of elastic scattering and fusion have been performed, including the inelastic excitations of projectile and target; the need for considering additional (transfer) channels is made evident. We also have indications that sub-barrier fusion is not merely tunneling through a potential barrier, although energy dependent, as absorption into fusion takes place at larger internuclear distances. Older fusion and quasielastic transfer data are overviewed and compared with the reaction cross sections extracted from elastic scattering. Open questions still remain about the role of specific channels in determining the observed isotopic differences.