Avian influenza A(H5) virus circulation in live bird markets in Vietnam, 2017-2022.

Background: Highly pathogenic avian influenza A(H5) human infections are a global concern, with many A(H5) human cases detected in Vietnam, including a case in October 2022. Using avian influenza virus surveillance from March 2017-September 2022, we described the percent of pooled samples that were positive for avian influenza A, A(H5), A(H5N1), A(H5N6), and A(H5N8) viruses in live bird markets (LBMs) in Vietnam.

Methods: Monthly at each LBM, 30 poultry oropharyngeal swab specimens and five environmental samples were collected.

Reported Global Avian Influenza Detections Among Humans and Animals During 2013-2022: Comprehensive Review and Analysis of Available Surveillance Data.

Background: Avian influenza (AI) virus detections occurred frequently in 2022 and continue to pose a health, economic, and food security risk. The most recent global analysis of official reports of animal outbreaks and human infections with all reportable AI viruses was published almost a decade ago. Increased or renewed reports of AI viruses, especially high pathogenicity H5N8 and H5N1 in birds and H5N1, H5N8, and H5N6 in humans globally, have established the need for a comprehensive review of current global AI virus surveillance data to assess the pandemic risk of AI viruses.

Amplification of pulsed light with arbitrary frequency chirps on nanosecond timescales.

We have developed a system for producing amplified pulses of frequency-chirped light at 780 nm on nanosecond timescales. The system starts with tunable cw laser light and employs a pair of fiber-based phase modulators, a semiconductor optical amplifier, and a tapered amplifier to achieve chirp rates exceeding 3 GHz/10 ns and peak powers greater than 1 W. Driving the modulators with an arbitrary waveform generator enables arbitrary chirp shapes, such as two-frequency linear chirps.

Environmental sampling for SARS-CoV-2 at a reference laboratory and provincial hospital in central Viet Nam, 2020.

Objective: To determine whether environmental surface contamination with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) occurred at a provincial hospital in Viet Nam that admitted patients with novel coronavirus disease 2019 (COVID-19) and at the regional reference laboratory responsible for confirmatory testing for SARS-CoV-2 in 2020.

Methods: Environmental samples were collected from patient and staff areas at the hospital and various operational and staff areas at the laboratory. Specimens from frequently touched surfaces in all rooms were collected using a moistened swab rubbed over a 25 cm area for each surface.

Burden of Influenza-Associated Respiratory Hospitalizations, Vietnam, 2014-2016.

Influenza burden estimates are essential to informing prevention and control policies. To complement recent influenza vaccine production capacity in Vietnam, we used acute respiratory infection (ARI) hospitalization data, severe acute respiratory infection (SARI) surveillance data, and provincial population data from 4 provinces representing Vietnam's major regions during 2014-2016 to calculate provincial and national influenza-associated ARI and SARI hospitalization rates. We determined the proportion of ARI admissions meeting the World Health Organization SARI case definition through medical record review.

Nanosecond pulse shaping at 780 nm with fiber-based electro-optical modulators and a double-pass tapered amplifier.

We describe a system for generating frequency-chirped and amplitude-shaped pulses on time scales from sub-nanosecond to ten nanoseconds. The system starts with cw diode-laser light at 780 nm and utilizes fiber-based electro-optical phase and intensity modulators, driven by an arbitrary waveform generator, to generate the shaped pulses. These pulses are subsequently amplified to several hundred mW with a tapered amplifier in a delayed double-pass configuration.

Efficient Formation of Ultracold Molecules with Chirped Nanosecond Pulses.

We describe experiments and associated quantum simulations involving the production of ultracold (87)Rb2 molecules with nanosecond pulses of frequency-chirped light. With appropriate chirp parameters, the formation is dominated by coherent processes. For a positive chirp, excited molecules are produced by photoassociation early in the chirp, and then transferred into high vibrational levels of the lowest triplet state by stimulated emission later in the chirp.

Enhancement of Ultracold Molecule Formation Using Shaped Nanosecond Frequency Chirps.

We demonstrate that judicious shaping of a nanosecond-time-scale frequency chirp can dramatically enhance the formation rate of ultracold (87)Rb(2) molecules. Starting with ultracold (87)Rb atoms, we apply pulses of frequency-chirped light to first photoassociate the atoms into excited molecules and then, later in the chirp, deexcite these molecules into a high vibrational level of the lowest triplet state a (3)Σ(u)(+). The enhancing chirp shape passes through the absorption and stimulated emission transitions relatively slowly, thus increasing their adiabaticity, but jumps quickly between them to minimize the effects of spontaneous emission.

Costs and consequences: Hepatitis C seroprevalence in the military and its impact on potential screening strategies.

Unlabelled: Knowledge of the contemporary epidemiology of hepatitis C viral (HCV) infection among military personnel can inform potential Department of Defense screening policy. HCV infection status at the time of accession and following deployment was determined by evaluating reposed serum from 10,000 service members recently deployed to combat operations in Iraq and Afghanistan in the period 2007-2010. A cost model was developed from the perspective of the Department of Defense for a military applicant screening program.

Spectroscopy and applications of the 3 3Σ+ electronic state of 39K85Rb.

We report new results on the spectroscopy of the 3 (3)Σ(+) electronic state of (39)K(85)Rb. The observations are based on resonance-enhanced multiphoton ionization of ultracold KRb molecules starting in vibrational levels v'' = 18-23 of the a (3)Σ(+) state and ionized via the intermediate 3 (3)Σ(+) state. The a-state ultracold molecules are formed by photoassociation of ultracold (39)K and (85)Rb atoms to the 3(0(+)) state of KRb followed by spontaneous emission.

Excitation of weakly bound molecules to trilobitelike Rydberg states.

We observe "trilobitelike" states of ultracold (85)Rb(2) molecules, in which a ground-state atom is bound by the electronic wave function of its Rydberg-atom partner. We populate these states through the ultraviolet excitation of weakly bound molecules, and access a regime of trilobitelike states at low principal quantum numbers and with vibrational turning points around 35 Bohr radii. This demonstrates that, unlike previous studies that used free-to-bound transitions, trilobitelike states can also be excited through bound-to-bound transitions.

Spectroscopy of the double minimum 3 (3)ΠΩ electronic state of 39K85Rb.

We report the observation and analysis of the 3 (3)ΠΩ double-minimum electronic excited state of (39)K(85)Rb. The spin-orbit components (0(+), 0(-), 1, and 2) of this state are investigated based on potentials developed from the available ab initio potential curves. We have assigned the vibrational levels v' = 2-11 of the 3 (3)Π1,2 potentials and v' = 2-12 of the 3(3)Π0(+/-) potential.

Spectroscopic investigation of the A and 3 1Σ+ states of 39K85Rb.

By using a combination of molecular beam (MB) excitation spectra and two distinct ultracold molecule excitation spectra (UM+ and UM-), we have assigned high vibrational levels of the A and 3 (1)Σ(+) states from absorption spectra of the mutually strongly perturbed A (1)Σ(+) - 3 (1)Σ(+) - 1 (1)Π - 2 (3)Σ(+) - b (3)Π states of ultracold (39)K(85)Rb molecules in the energy region between 15,116 and 16,225 cm(-1) above the minimum of the ground X (1)Σ(+) state. The ultracold molecules (UM+ and UM-) are formed by radiative decay following photoassociation (PA) to a specific level of the 3(0(+)) state (UM+) or to a specific level of the 3(0(-)) state (UM-). We observe that the A and 3 (1)Σ(+) states are observable in the UM+ spectra, but absent from the UM- spectra.

Observation of a resonant four-body interaction in cold cesium Rydberg atoms.

Cold Rydberg atoms subject to long-range dipole-dipole interactions represent a particularly interesting system for exploring few-body interactions and probing the transition from 2-body physics to the many-body regime. In this work we report the direct observation of a resonant 4-body Rydberg interaction. We exploit the occurrence of an accidental quasicoincidence of a 2-body and a 4-body resonant Stark-tuned Förster process in cesium to observe a resonant energy transfer requiring the simultaneous interaction of at least four neighboring atoms.

Review of non-battle injuries in Air Force personnel deployed in support of Operation Enduring Freedom and Operation Iraqi Freedom.

This study examines non-battle injuries among U.S. Air Force members deployed during Operations Iraqi and Enduring Freedom.

Formation of ultracold Rb2 molecules in the v'' = 0 level of the a(3)Σ+(u) state via blue-detuned photoassociation to the 1(3)Π(g) state.

We report on the observation of blue-detuned photoassociation in Rb(2), in which vibrational levels are energetically above the corresponding excited atomic asymptote. (85)Rb atoms in a MOT were photoassociated at short internuclear distance to levels of the 1(3)Π(g) state at a rate of approximately 5 × 10(4) molecules s(-1). We have observed most of the predicted vibrational levels for all four spin-orbit components; 0(+)(g), 0(-)(g), 1(g), and 2(g), including levels of the 0(+)(g) outer well.

Spectroscopic analysis of the coupled 1(1)Π, 2(3)Σ+ (Ω = 0-, 1), and b(3)Π (Ω = 0±, 1, 2) states of the KRb molecule using both ultracold molecules and molecular beam experiments.

We report the spectroscopic characterization of excited electronic states of KRb by combining spectra from molecular beam (MB) experiments with those from ultracold molecules (UM) formed by photoassociation (PA) of ultracold atoms. Spectra involving the 1(1)Π, 2(3)Σ(+), and b(3)Π states in a strongly perturbed region have been identified. This approach provides a powerful method to identify the vibrational levels of the excited electronic states perturbed globally by neighboring electronic states.

Creation of arbitrary time-sequenced line spectra with an electro-optic phase modulator.

We use a waveguide-based electro-optic phase modulator, driven by a nanosecond-timescale arbitrary waveform generator, to produce an optical spectrum with an arbitrary pattern of peaks. A programmed sequence of linear voltage ramps, with various slopes, is applied to the modulator. The resulting phase ramps give rise to peaks whose frequency offsets relative to the carrier are equal to the slopes of the corresponding linear phase ramps.

Characterization and compensation of the residual chirp in a Mach-Zehnder-type electro-optical intensity modulator.

We utilize various techniques to characterize the residual phase modulation of a waveguide-based Mach-Zehnder electro-optical intensity modulator. A heterodyne technique is used to directly measure the phase change due to a given change in intensity, thereby determining the chirp parameter of the device. This chirp parameter is also measured by examining the ratio of sidebands for sinusoidal amplitude modulation.

Health care transmission of a newly emergent adenovirus serotype in health care personnel at a military hospital in Texas, 2007.

Background: Adenoviruses can cause outbreaks of febrile respiratory illness in military trainees, but until 2007, adenovirus serotype 14 (Ad14) was never associated with such outbreaks. From April through June 2007, 15 trainees at one base were hospitalized for pneumonia due to Ad14. Subsequent reports of febrile respiratory illness among health care personnel suggested nosocomial transmission.

An outbreak of varicella in elementary school children with two-dose varicella vaccine recipients--Arkansas, 2006.

Background: In June 2006, the Advisory Committee on Immunization Practices (ACIP) expanded its June 2005 recommendation for a second dose of varicella vaccine during outbreaks to a recommendation for routine school entry second dose varicella vaccination. In October 2006, the Arkansas Department of Health was notified of a varicella outbreak among students where some received a second dose during an outbreak-related vaccination campaign in February 2006.

Methods: The outbreak was investigated using a school-wide parental survey with a follow-up survey of identified case patients.

Reproductive tract complications associated with Chlamydia trachomatis infection in US Air Force males within 4 years of testing.

Background: Chlamydia trachomatis (CT) is a common sexually transmitted infection for which young, sexually active persons are at highest risk. Health consequences such as orchitis/epididymitis, prostatitis, infertility, and urethral stricture have been described among CT-infected males, although not all of these are indisputably linked to CT. Current literature lacks population-based studies needed to examine these associations on a larger scale, to evaluate the true risk of developing complications after a CT infection.