Radiocarbon in marine bacteria: Evidence for the ages of assimilated carbon

It is generally accepted that marine bacteria utilize labile, recently produced components of bulk dissolved organic matter. This interpretation is based largely on indirect measurements using model compounds and plankton-derived organic matter. Here, we present an assessment of the relative proportions of modem and older dissolved organic carbon (DOC) utilized by marine bacteria. Bacterial nucleic acids were collected from both estuarine (Santa Rosa Sound, FL) and open-ocean (eastern North Pacific) sites, and the natural radiocarbon signatures of the nucleic acid carbon in both systems were determined. Bacterial nucleic acids from Santa Rosa Sound were significantly enriched in radiocarbon with respect to the bulk DOC and were similar to the radiocarbon signature of atmospheric CO2 at the time of sampling, indicating that these bacteria exclusively assimilate a modem component of the estuarine bulk DOG. In contrast, bacterial nucleic acids from the oceanic site were enriched in C-14 relative to the bulk DOC but depleted in C-14 with respect to modem surface dissolved inorganic carbon (DIC) and suspended particulate organic carbon (POCsusp). This suggests that open-ocean bacteria assimilate both modem and older components of DOG. The distinct radiocarbon signatures of the nucleic acids at these two sites (i.e., +120 +/- 17% estuarine vs. -34 +/- 24% oceanic) demonstrate that natural C-14 abundance measurements of bacterial biomarkers are a powerful tool for investigations of carbon cycling through microbial communities in different aquatic systems

Liquid Saturation and Gas-Liquid Distribution in Multiphase Monolithic Reactors

The Monolith Bed is One of the Promising Catalytic Reactors for a Number of Chemical Gas-Liquid-Solid Processes. in the Present Work, Liquid Saturations for Five Different Monoliths Have Been Investigated Experimentally in a Cold-Flow Unit with a Reactor Diameter of 5.0 Cm. the Influences of Gas and Liquid Flow Rates and of the Direction of Two-Phase Flow on Liquid Saturation Were Examined. the Results Indicate that the Direction of Flow Has No Significant Influence on Liquid Saturation for Proper Gas-Liquid Distribution. the Experimental Results Are in Good Agreement with Predictions of the Drift Flux Model using the Distribution Parameter Proposed by Ishii (ANL Report ANL-77-47, 1977) Along with the Assumption of Zero Drift Velocity. in Preliminary Experiments, Gamma-Ray Computed Tomography (CT) Has Been Successfully Applied to Measure Time-Averaged Liquid Distribution over the Monolith Cross-Section in a Selected Condition. the Employment of a Nozzle-Type Distributor Provides an Almost Uniform Liquid Distribution over the Monolith Substrate. It is Demonstrated that CT is a Viable Technique for Studying Two-Phase Flow in Laboratory-Scale Monolith Reactors. © 2005 Elsevier Ltd. All Rights Reserved

A Common Love of Science: The One-Hundredth Meeting of the American Society of Ichthyologists and Herpetologists

One of the most important functions of an academic society such as the American Society of Ichthyologists and Herpetologists (ASIH) is to host conferences for colleagues to directly share and debate ideas and data. Academic society meetings have a long history that grew from social meetings of the privileged in the 16th and 17th centuries during which scientific topics were discussed. Scientific meetings of any nature can provide a stimulating environment to discuss and argue points (Unglow, 2002), as alluded to by Joseph Priestley (1733–1804) in the epigraph, which was written with fond memory of the Lunar Society meetings while he was in political exile (Priestley, 1793). In 1812, a gathering of local scientists formally established The Academy of Natural Sciences of Philadelphia (ANSP), a society “to occupy their leisure, in each other\u27s company, on subjects of natural science” for “the advancement and diffusion of useful, liberal human knowledge.” The founders agreed that the ANSP would be “perpetually exclusive of political, religious and national partialities, antipathies, preventions and prejudices” to avoid potential conflicts with “the interests of science” (Stroud, 1997: 227). With the rise and specialization of academic societies, a concomitant specialization of scientific gatherings followed. Narrowly focused meetings have an important role in advancing the field specific to their topic, but regular (i.e., annual) discipline-wide conferences are important for both the tangible (e.g., presentation of fact) and intangible (e.g., inspiration of new avenues of study) effects they have on the attendees. Conferences also allow attendees the opportunity to conduct Society business through board and committee meetings. In 2021, the ASIH held its 100th in-person meeting, the third and final centennial to be celebrated by this Society (2013 was the 100th year of the Society\u27s journal, Copeia, now Ichthyology & Herpetology, Smith and Mitchell, 2013; 2016 was the 100th year of the ASIH\u27s founding, Hilton and Crump, 2016). This paper celebrates this milestone of the ASIH, and reflects upon the history of the ASIH conferences

Excited Boundary TBA in the Tricritical Ising Model

By considering the continuum scaling limit of the $A_{4}$ RSOS lattice model of Andrews-Baxter-Forrester with integrable boundaries, we derive excited state TBA equations describing the boundary flows of the tricritical Ising model. Fixing the bulk weights to their critical values, the integrable boundary weights admit a parameter $\xi$ which plays the role of the perturbing boundary field $\phi_{1,3}$ and induces the renormalization group flow between boundary fixed points. The boundary TBA equations determining the RG flows are derived in the $\mathcal{B}_{(1,2)}\to \mathcal{B}_{(2,1)}$ example. The induced map between distinct Virasoro characters of the theory are specified in terms of distribution of zeros of the double row transfer matrix.Comment: Latex, 14 pages - Talk given at the Landau meeting "CFT and Integrable Models", Sept. 2002 - v2: some statements about $\phi_{1,2}$ perturbations correcte

Entropies, volumes, and Einstein metrics

We survey the definitions and some important properties of several asymptotic invariants of smooth manifolds, and discuss some open questions related to them. We prove that the (non-)vanishing of the minimal volume is a differentiable property, which is not invariant under homeomorphisms. We also formulate an obstruction to the existence of Einstein metrics on four-manifolds involving the volume entropy. This generalizes both the Gromov--Hitchin--Thorpe inequality and Sambusetti's obstruction.Comment: This is a substantial revision and expansion of the 2004 preprint, which I prepared in spring of 2010 and which has since been published. The version here is essentially the published one, minus the problems introduced by Springer productio

Plasma exchange in the intensive care unit: a narrative review

In this narrative review, we discuss the relevant issues of therapeutic plasma exchange (TPE) in critically ill patients. For many conditions, the optimal indication, device type, frequency, duration, type of replacement fluid and criteria for stopping TPE are uncertain. TPE is a potentially lifesaving but also invasive procedure with risk of adverse events and complications and requires close monitoring by experienced teams. In the intensive care unit (ICU), the indications for TPE can be divided into (1) absolute, well-established, and evidence-based, for which TPE is recognized as first-line therapy, (2) relative, for which TPE is a recognized second-line treatment (alone or combined) and (3) rescue therapy, where TPE is used with a limited or theoretical evidence base. New indications are emerging and ongoing knowledge gaps, notably regarding the use of TPE during critical illness, support the establishment of a TPE registry dedicated to intensive care medicine

Factorization and Nonfactorization in B Decays

Using NLL values for Wilson coefficients and including the contributions from the penguin diagrams, we estimate the amount of nonfactorization in two-body hadronic B decays. Also, we investigate the model dependence of the nonfactorization parameters by performing the calculation using different models for the form factors. The results support the universality of nonfactorizable contributions in both Cabibbo-favored and Cabibbo-suppressed B decays.Comment: 17 pages, 5 figures, revte

Non-factorizable long distance contributions in color suppressed decays of B mesons

$\bar B \to D\pi$, $D^*\pi$, $J/\psi\bar K$ and $J/\psi\pi$ decays are studied. Their amplitude is given by a sum of factorized and non-factorizable ones. The latter which is estimated by using a hard pion approximation is rather small in color favored $\bar B \to D\pi$ and $D^*\pi$ decays but still can efficiently interfere with the main amplitude given by the factorization. In the color suppressed $\bar B \to J/\psi\bar K$ and $J/\psi\pi$ decays, the non-factorizable contribution is very important. The sum of the factorized and non-factorizable amplitudes can reproduce well the existing experimental data on the branching ratios for the color favored $\bar B \to D\pi$ and $D^*\pi$ and the color suppressed $\bar B \to J/\psi \bar K$ and $J/\psi\pi$ decays by taking reasonable values of unknown parameters involved.Comment: 19 pages, Revte