Comparison of Two Separation Methods for Biological Particles: Field-Flow Fractionation (FFF) and Sucrose Density Gradients

Sucrose gradient centrifugation and Field-flow fractionation (FFF) are two different particle separation methods that overcome the problems of similar size microorganisms clumping together during standard filtration methods. FFF separates particles based on size and density via the parabolic velocity profile of laminar flow in a ribbon-like channel. The sucrose method separates particles via centrifugation in a density gradient. Both techniques worked well in separating eukaryotic from prokaryotic microbes, with the preferred method depending on the type and relative abundance of organisms to be separated. Minicells were separated from mother cells in transformed Escherichia coli cultures, heterotrophic flagellates (e.g., Diplonema papillatum) from their bacterial prey in cultures, and various eukaryotes from prokaryotes in natural seawater communities. These separated clean fractions were further analyzed for their biochemical composition (using radiolabeling and subsequent biochemical fractionation) revealing significant differences in the bulk biochemical makeup between prokaryotic and eukaryotic microbes. Even within domains, the sucrose gradient method was able to separate prokaryotic and eukaryotic microbes by size. Variables that influence and improve these separation techniques were explored, including the effect of aldehyde fixation

The Determining Number and Cost of 2-Distinguishing of Select Kneser Graphs

A graph $G$ is said to be \emph{d-distinguishable} if there exists a not-necessarily proper coloring with $d$ colors such that only the trivial automorphism preserves the color classes. For a 2-distinguishing labeling, the \emph{ cost of $2$-distinguishing}, denoted $\rho(G),$ is defined as the minimum size of a color class over all $2$-distinguishing colorings of $G$. Our work also utilizes \emph{determining sets} of $G,$ sets of vertices $S \subseteq G$ such that every automorphism of $G$ is uniquely determined by its action on $S.$ The \emph{determining number} of a graph is the size of a smallest determining set. We investigate the cost of $2$-distinguishing families of Kneser graphs $K_{n:k}$ by using optimal determining sets of those families. We show the determining number of \kntwo is equal to $\left\lceil{ \frac{2n-2}{3}}\right\rceil$and give linear bounds on \rho(\kntwo) when $n$ is sufficiently sized

The Ghosts of Infertility: haunted by the realities of reproductive death

The use of graphics in academic research is a relatively underexplored and underutilized medium through which social science researcher s can communicate and share the knowledge they’ve acquired with larger audiences. The graphic article attempts to disseminate the findings of sociological research to non-academic audiences in an effort to make more public and more accessible the information intended to help regular people in everyday life. This article will use autoethnography in addition to critical discourse analysis to expose the connections between the ways in which female-bodied people experience psycho-medical discourses in everyday interaction, and in more institutionalized settings (i.e. doctor’s offices). The character featured in this piece serves as an amalgam to tell the stories of many female-bodied people’s stories. Using the Diagnostic and Statistical Manual of Mental Disorders as a guide through “hysteria” and “hypochondriasis,” this graphic narrative will explore the social exchanges of this fictional character as she asks questions about aging, reproduction, and gendered ideological frameworks set in motion by academic/medical discourses in her everyday life. Providing evidence of physio-biological changes in her body, her questions and stories prove to reveal responses in her interactions that are not only interestingly similar, but also strangely framed as comfort and dismissals of her embodied experiences

Riccati parameter modes from Newtonian free damping motion by supersymmetry

We determine the class of damped modes \tilde{y} which are related to the common free damping modes y by supersymmetry. They are obtained by employing the factorization of Newton's differential equation of motion for the free damped oscillator by means of the general solution of the corresponding Riccati equation together with Witten's method of constructing the supersymmetric partner operator. This procedure leads to one-parameter families of (transient) modes for each of the three types of free damping, corresponding to a particular type of %time-dependent angular frequency. %time-dependent, antirestoring acceleration (adding up to the usual Hooke restoring acceleration) of the form a(t)=\frac{2\gamma ^2}{(\gamma t+1)^{2}}\tilde{y}, where \gamma is the family parameter that has been chosen as the inverse of the Riccati integration constant. In supersymmetric terms, they represent all those one Riccati parameter damping modes having the same Newtonian free damping partner modeComment: 6 pages, twocolumn, 6 figures, only first 3 publishe

Physical Development of Women.

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Sources of Oospora lactis on dairy farms

Publication authorized February 24, 1945.Includes bibliographical references (pages 14-15)

San Bruno Mountain wind investigation, a wind-tunnel model study

CER67-68JEC-JAG58.April 1968.Prepared under contract with Metronics Associates, Inc. for Wilsey and Ham, Consulting Engineers

Wind-tunnel studies of winds in Candlestick Park

CER70-71JAG-JEC5.May 1970.Includes bibliographical references (page 16).Prepared for City of San Francisco Department of Public Works.The purpose of this investigation is to determine if any low-cost, light-weight modification can be made either to the existing structure of Candlestick Park or to the proposed addition to improve the disturbing wind conditions now experienced in the stadium. The proposed addition will extend the upper spectator stands to completely enclose the playing field. A previous wind-tunnel study of winds in Candlestick Park found that the modeling technique yields wind patterns which correlate well with prototype patterns measured in a field study. The study conducted in 1963 also revealed that a combination of modifications to Bay View Hill and a partial dome over the stadium or a 60 ft high screen around the upper stands would be effective in elimination of objectionable features of the wind flow within the stadium. It proved impractical to make these modifications at that time. Since 1963, the southeast end of Bay View Hill has been modified further by excavations in a manner which the model study showed would improve the wind conditions. Therefore, the present study was undertaken with the hope that improvement of wind conditions might possibly be achieved through small changes in the existing or new portions of the stadium structure. This investigation has confirmed findings of-the previous study that simply extending the upper stands around the entire playing field will result in only a small improvement -and that the modifications to Bay View Hill have not been extensive enough to be of significant consequence. As found previously, it was observed that a SO to 100 ft screen around much of the upper stands and extending above the roof has a beneficial effect. None of the minor modifications investigated appeared to offer any significant level of wind control