Strongly Coupled Plasmas via Rydberg-Blockade of Cold Atoms

We propose and analyze a new scheme to produce ultracold neutral plasmas deep in the strongly coupled regime. The method exploits the interaction blockade between cold atoms excited to high-lying Rydberg states and therefore does not require substantial extensions of current ultracold plasma experiments. Extensive simulations reveal a universal behavior of the resulting Coulomb coupling parameter, providing a direct connection between the physics of strongly correlated Rydberg gases and ultracold plasmas. The approach is shown to reduce currently accessible temperatures by more than an order of magnitude, which opens up a new regime for ultracold plasma research and cold ion-beam applications with readily available experimental techniques.Comment: 5 pages, 5 figure

Creating Non-Maxwellian Velocity Distributions in Ultracold Plasmas

We present techniques to perturb, measure and model the ion velocity distribution in an ultracold neutral plasma produced by photoionization of strontium atoms. By optical pumping with circularly polarized light we promote ions with certain velocities to a different spin ground state, and probe the resulting perturbed velocity distribution through laser-induced fluorescence spectroscopy. We discuss various approaches to extract the velocity distribution from our measured spectra, and assess their quality through comparisons with molecular dynamic simulationsComment: 13 pages, 8 figure

Velocity Relaxation in a Strongly Coupled Plasma

Collisional relaxation of Coulomb systems is studied in the strongly coupled regime. We use an optical pump-probe approach to manipulate and monitor the dynamics of ions in an ultracold neutral plasma, which allows direct measurement of relaxation rates in a regime where common Landau-Spitzer theory breaks down. Numerical simulations confirm the experimental results and display non-Markovian dynamics at early times.Comment: 5 pages, 5 figure

Observations on the Use of the GnRH Vaccine GonaCon™ in the Male White-Tailed Deer (Odocoileus virginianus)

Observations made over an 11 year period during the development and evaluation of the GnRH vaccine GonaConTM use in male white-tailed deer (Odocoileus virginianus) are summarized. Sexually mature bucks at the Penn State Deer Research Center were administered a single immunization of GonaConTM in July. Some males were also given a second boost immunization in September. Compared to similar aged controls, testicular size for treated males was considerably reduced in the first and subsequent years of study, as were testosterone concentrations and sexual libido. During the first year, antler development was relatively normal leading to antler hardening, although shedding occurred early. However, in subsequent years, antlers were generally smaller, remained in velvet throughout the winter, and froze and then broke off. Most males given the single immunization returned to breeding condition in 2-3 years, although they tended to be smaller than similar-aged males. Males given the two immunizations tended to remain in a treated state longer. Treated males that died during the study had a higher incidence of pulmonary disease than non-treated males. We conclude that while GonaConTM reduces the reproductive capacity of male white-tailed deer, the negative effects on health and antler development make it impractical for field application with bucks

Observations on the Use of the GnRH Vaccine Gonacon™ in Male White-Tailed Deer (\u3ci\u3eOdocoileus virginianus\u3c/i\u3e)

Observations made over an 11 year period during the development and evaluation of the GnRH vaccine GonaCon™ use in male white-tailed deer (Odocoileus virginianus) are summarized. Sexually mature bucks at the Penn State Deer Research Center were administered a single immunization of GonaCon™ in July. Some males were also given a second boost immunization in September. Compared to similar aged controls, testicular size for treated males was considerably reduced in the first and subsequent years of study, as were testosterone concentrations and sexual libido. During the first year, antler development was relatively normal leading to antler hardening, although shedding occurred early. However, in subsequent years, antlers were generally smaller, remained in velvet throughout the winter, and froze and then broke off. Most males given the single immunization returned to breeding condition in 2-3 years, although they tended to be smaller than similar-aged males. Males given the two immunizations tended to remain in a treated state longer. Treated males that died during the study had a higher incidence of pulmonary disease than non-treated males. We conclude that while GonaCon™ reduces the reproductive capacity of male white-tailed deer, the negative effects on health and antler development make it impractical for field application with bucks

Bose-Einstein Condensation of 88^{88}Sr Through Sympathetic Cooling with 87^{87}Sr

We report Bose-Einstein condensation of $^{88}$Sr, which has a small, negative s-wave scattering length ($a_{88}=-2$\,$a_0$). We overcome the poor evaporative cooling characteristics of this isotope by sympathetic cooling with $^{87}$Sr atoms. $^{87}$Sr is effective in this role in spite of the fact that it is a fermion because of the large ground state degeneracy arising from a nuclear spin of $I=9/2$, which reduces the impact of Pauli blocking of collisions. We observe a limited number of atoms in the condensate ($N_{max}\approx 10^4$) that is consistent with the value of $a_{88}$ and the optical dipole trap parameters.Comment: 4 pages, 4 figure

Clinicopathological determinants of an elevated systemic inflammatory response following elective potentially curative resection for colorectal cancer

Introduction: The postoperative systemic inflammatory response (SIR) is related to both long- and short-term outcomes following surgery for colorectal cancer. However, it is not clear which clinicopathological factors are associated with the magnitude of the postoperative SIR. The present study was designed to determine the clinicopathological determinants of the postoperative systemic inflammatory response following colorectal cancer resection. Methods: Patients with a histologically proven diagnosis of colorectal cancer who underwent elective, potentially curative resection during a period from 1999 to 2013 were included in the study (n = 752). Clinicopathological data and the postoperative SIR, as evidenced by postoperative Glasgow Prognostic Score (poGPS), were recorded in a prospectively maintained database. Results: The majority of patients were aged 65 years or older, male, were overweight or obese, and had an open resection. After adjustment for year of operation, a high day 3 poGPS was independently associated with American Society of Anesthesiologists (ASA) grade (hazard ratio [HR] 1.96; confidence interval [CI] 1.25–3.09; p = 0.003), body mass index (BMI) (HR 1.60; CI 1.07–2.38; p = 0.001), mGPS (HR 2.03; CI 1.35–3.03; p = 0.001), and tumour site (HR 2.99; CI 1.56–5.71; p < 0.001). After adjustment for year of operation, a high day 4 poGPS was independently associated with ASA grade (HR 1.65; CI 1.06–2.57; p = 0.028), mGPS (HR 1.81; CI 1.22–2.68; p = 0.003), NLR (HR 0.50; CI 0.26–0.95; p = 0.034), and tumour site (HR 2.90; CI 1.49–5.65; p = 0.002). Conclusions: ASA grade, BMI, mGPS, and tumour site were consistently associated with the magnitude of the postoperative systemic inflammatory response, evidenced by a high poGPS on days 3 and 4, in patients undergoing elective potentially curative resection for colorectal cancer

Ultracold Neutral Plasmas

Ultracold neutral plasmas are formed by photoionizing laser-cooled atoms near the ionization threshold. Through the application of atomic physics techniques and diagnostics, these experiments stretch the boundaries of traditional neutral plasma physics. The electron temperature in these plasmas ranges from 1-1000 K and the ion temperature is around 1 K. The density can approach $10^{11}$ cm$^{-3}$. Fundamental interest stems from the possibility of creating strongly-coupled plasmas, but recombination, collective modes, and thermalization in these systems have also been studied. Optical absorption images of a strontium plasma, using the Sr$^+$ ${^2S\_{1/2}} -> {^2P\_{1/2}}$ transition at 422 nm, depict the density profile of the plasma, and probe kinetics on a 50 ns time-scale. The Doppler-broadened ion absorption spectrum measures the ion velocity distribution, which gives an accurate measure of the ion dynamics in the first microsecond after photoionization.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France

Runaway evaporation for optically dressed atoms

Forced evaporative cooling in a far-off-resonance optical dipole trap is proved to be an efficient method to produce fermionic- or bosonic-degenerated gases. However in most of the experiences, the reduction of the potential height occurs with a diminution of the collision elastic rate. Taking advantage of a long-living excited state, like in two-electron atoms, I propose a new scheme, based on an optical knife, where the forced evaporation can be driven independently of the trap confinement. In this context, the runaway regime might be achieved leading to a substantial improvement of the cooling efficiency. The comparison with the different methods for forced evaporation is discussed in the presence or not of three-body recombination losses