Knowing When to Fold\u27em: A Monte Carlo Exploration of Card Shuffling and How Poker Players Can Gain an Advantage

This work demonstrates that the card shuffling procedure commonly performed in casino poker rooms is insufficient for randomizing a deck of cards. We explore this in the context of Texas Hold’em, which has established itself as the most popular form of poker worldwide over the past few decades. We show the degree to which the resulting distribution of the orderings of all 52 cards in the deck after shuffling is not uniform. Rather, any given card may be substantially more (or less) likely to show up as an important card in the subsequent hand. Additionally, we find that the shuffling procedure does not sufficiently separate cards from their starting point; that is, cards are more likely to stay close together after shuffling than they should by chance. Thus, in this work, we demonstrate that Texas Hold’em players can gain an advantage over their opponents by recognizing these deficiencies in the shuffling procedure

Risk factors for Kaposi's sarcoma in human immunodeficiency virus patients after initiation of antiretroviral therapy: A nested case–control study in Kenya

AbstractBackground/PurposeThis study aimed to evaluate the association between highly active antiretroviral therapy (HAART) adherence and development of Kaposi's sarcoma (KS) in human immunodeficiency virus (HIV)/AIDS patients.MethodsWe conducted a retrospective nested case–control study of 165 participants (33 cases and 132 controls) receiving HAART care at Maseno Hospital, Kenya, from January 2005 to October 2013. Cases were HIV-positive adults with KS, who were matched with controls in a ratio of 1:4 based on age (±5 years of each case), sex, and KS diagnosis date. Perfect adherence to HAART was assessed on every clinic visit by patients' self-reporting and pill counts. Chi-square tests were performed to compare socioeconomic and clinical statuses between cases and controls. A conditional logistic regression was used to assess the effects of perfect adherence to HAART, the latest CD4 count, education level, distance to health-care facility, initial World Health Organization stage, and number of regular sexual partners on the development of KS.ResultsOnly 63.6% participants reported perfect adherence, and the control group had a significantly higher percentage of perfect adherence (75.0%) than did cases (18.2%). After adjustment for potential imbalances in the baseline and clinical characteristics, patients with imperfect HAART adherence had 20-times greater risk of developing KS than patients with perfect HAART adherence [hazard ratios: 21.0, 95% confidence interval: 4.2–105.1]. Patients with low latest CD4 count (≤350 cells/mm3) had a seven-times greater risk of developing KS than did their counterparts (HRs: 7.1, 95% CI: 1.4–36.2).ConclusionImperfect HAART adherence and low latest CD4 count are significantly associated with KS development

Synonymous and Nonsynonymous Distances Help Untangle Convergent Evolution and Recombination

When estimating a phylogeny from a multiple sequence alignment, researchers often assume the absence of recombination. However, if recombination is present, then tree estimation and all downstream analyses will be impacted, because different segments of the sequence alignment support different phylogenies. Similarly, convergent selective pressures at the molecular level can also lead to phylogenetic tree incongruence across the sequence alignment. Current methods for detection of phylogenetic incongruence are not equipped to distinguish between these two different mechanisms and assume that the incongruence is a result of recombination or other horizontal transfer of genetic information. We propose a new recombination detection method that can make this distinction, based on synonymous codon substitution distances. Although some power is lost by discarding the information contained in the nonsynonymous substitutions, our new method has lower false positive probabilities than the comparable recombination detection method when the phylogenetic incongruence signal is due to convergent evolution. We apply our method to three empirical examples, where we analyze: 1) sequences from a transmission network of the human immunodeficiency virus, 2) tlpB gene sequences from a geographically diverse set of 38 Helicobacter pylori strains, and 3) Hepatitis C virus sequences sampled longitudinally from one patient.Comment: 21 pages, 8 figures, updated abstrac

Copper vapor laser machining of polyimide and polymethylmethacrylate in atmospheric pressure air

A repetitively pulsed copper vapor laser (510 and 578 nm) is used to machine an opaque polymer (polyimide‐Vespel) and a transparent polymer (polymethylmethacrylate‐Lucite). Lucite is machinable by coating the surface with an ink which is semi‐opaque to the green and yellow laser light. The repetition rate of the laser was 10 kHz with approximately 0.35 mJ/pulse and 3.5 W average power at the copper vapor laser wavelengths for a pulse width of 40 ns. The copper vapor laser thermally loads the target, generating thermal waves and sound waves in the gas which are investigated using HeNe laser beam deflection. The gas adjacent to the target is heated to steady state on the order of 100–400 s. Above the etching threshold, at approximately 10 mJ/cm2/pulse, the target is rapidly machined: 2‐mm‐diam, 2‐mm‐deep holes are drilled in 300 s in Vespel. At higher fluences of 100–150 mJ/cm2/pulse in 760 Torr of air it takes 180 s to bore through a 2‐mm‐thick disk of Vespel. The machined surfaces of the two polymers are very different. Machined Vespel samples are charred and cratered, whereas the Lucite samples show evidence of melting with little charring. The machining of polymers by visible‐light copper vapor lasers is being compared to UV photoablation by KrF excimer laser light in order to study thermal versus nonthermal etching mechanisms.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71173/2/JAPIAU-72-7-3080-1.pd

Higher order Jordan Osserman Pseudo-Riemannian manifolds

We study the higher order Jacobi operator in pseudo-Riemannian geometry. We exhibit a family of manifolds so that this operator has constant Jordan normal form on the Grassmannian of subspaces of signature (r,s) for certain values of (r,s). These pseudo-Riemannian manifolds are new and non-trivial examples of higher order Osserman manifolds

Repression of nodal expression by maternal B1-type SOXs regulates germ layer formation in Xenopus and zebrafish

AbstractB1-type SOXs (SOXs 1, 2, and 3) are the most evolutionarily conserved subgroup of the SOX transcription factor family. To study their maternal functions, we used the affinity-purified antibody antiSOX3c, which inhibits the binding of Xenopus SOX3 to target DNA sequences [Development. 130(2003)5609]. The antibody also cross-reacts with zebrafish embryos. When injected into fertilized Xenopus or zebrafish eggs, antiSOX3c caused a profound gastrulation defect; this defect could be rescued by the injection of RNA encoding SOX3ΔC-EnR, a SOX3-engrailed repression domain chimera. In antiSOX3c-injected Xenopus embryos, normal animal–vegetal patterning of mesodermal and endodermal markers was disrupted, expression domains were shifted toward the animal pole, and the levels of the endodermal markers SOX17 and endodermin increased. In Xenopus, SOX3 acts as a negative regulator of Xnr5, which encodes a nodal-related TGFβ-family protein. Two nodal-related proteins are expressed in the early zebrafish embryo, squint and cyclops; antiSOX3c-injection leads to an increase in the level of cyclops expression. In both Xenopus and zebrafish, the antiSOX3c phenotype was rescued by the injection of RNA encoding the nodal inhibitor Cerberus-short (CerS). In Xenopus, antiSOX3c's effects on endodermin expression were suppressed by injection of RNA encoding a dominant negative version of Mixer or a morpholino against SOX17α2, both of which act downstream of nodal signaling in the endoderm specification pathway. Based on these data, it appears that maternal B1-type SOX functions together with the VegT/β-catenin system to regulate nodal expression and to establish the normal pattern of germ layer formation in Xenopus. A mechanistically conserved system appears to act in a similar manner in the zebrafish

Pressure, stress, and strain distribution in the double-stage diamond anvil cell

Double stage diamond anvil cells (DAC) of two designs have been assembled and tested. We used a standard symmetric DAC as a primary stage and CVD microanvils machined by a focused ion beam - as a second. We evaluated pressure, stress, and strain distributions in Au and Fe-Au samples as well as in secondary anvils using synchrotron x-ray diffraction with a micro-focused beam. A maximum pressure of 240 GPa was reached independent of the first stage anvil culet size. We found that the stress field generated by the second stage anvils is typical of conventional DAC experiments. The maximum pressures reached are limited by strains developing in the secondary anvil and by cupping of the first stage diamond anvil in the presented experimental designs. Also, our experiments show that pressures of several megabars may be reached without sacrificing the first stage diamond anvils

Nano-Immunodetection and Quantification of Mycobacteria in Metalworking Fluids

The accurate detection and enumeration of mycobacteria in metalworking fluids (MWFs) is imperative from an environmental protection and occupational health perspective. We report here on a comparison of the labeling efficiency of nano-immunomagnetic particles (NIMP) and free antibody (FAb) to detect mycobacteria in semisynthetic MWF by using both traditional visualization analysis and cluster analysis aided visualization analysis (CAAVA). The NIMP labeling method involved coating nanometer-scale magnetic particles with Protein A, and oriented conjugation of polyclonal antibodies specific to Mycobacterium spp. The FAb labeling method is modified from the traditional immunofluorescence (IF) method for more efficient detection of mycobacteria in a model MWF. The labeling efficiency of NIMP and FAb were 7.2 ± 4.6 and 16.3 ± 5.5%, and the specificity 85.0 ± 6.1 and 88.1 ± 10.5%, respectively, based on traditional visualization analysis. Based on CAAVA analysis, the labeling efficiency of NIMP and FAb increased to 12.4 ± 1.6 and 20.5 ± 3.9%, and the specificity to 97.8 ± 3.2 and 98.5 ± 2.5%, respectively. A linear relationship of FCM counts and seeded concentrations was observed over four orders of magnitude (R 2 ≤ 0.99) in pure and ternary cultures. The results strongly support the applicability of either FAb or NIMP coupled with CAAVA and flow cytometry for rapid detection and enumeration of mycobacteria in complex matrices.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63114/1/ees.2007.24.58.pd

Long-term nitrogen addition raises the annual carbon sink of a boreal forest to a new steady-state

The boreal forest is an important global carbon (C) sink. Since low soil nitrogen (N) availability is commonly a key constraint on forest productivity, the prevalent view is that increased N input enhances its C sink-strength. This understanding however relies primarily on observations of increased aboveground tree biomass and soil C stock following N fertilization, whereas empirical data evaluating the effects on the whole ecosystem-scale C balance are lacking. Here we use a unique long-term experiment consisting of paired forest stands with eddy covariance measurements to explore the effect of ecosystem-scale N fertilization on the C balance of a managed boreal pine forest. We find that the annual C uptake (i.e. net ecosystem production, NEP) at the fertilized stand was 16 +/- 2% greater relative to the control stand by the end of the first decade of N addition. Subsequently, the ratio of NEP between the fertilized and control stand remained at a stable level during the following five years with an average NEP to N response of 7 & PLUSMN; 1 g C per g N. Our study reveals that this non-linear response of NEP to long-term N fertilization was the result of a cross-seasonal feedback between the N-induced increases in both growing-season C uptake and subsequent winter C emission. We further find that one decade of N addition altered the sensitivity of ecosystem C fluxes to key environmental drivers resulting in divergent responses to weather patterns. Thus, our study highlights the need to account for ecosystem-scale responses to perturbations to improve our understanding of nitrogen-carbon-climate feedbacks in boreal forests.Peer reviewe