The legacy of immigration policies and employment exclusion: Assessing the relationship between employment exclusions and immigrant health.

Restrictive federal and state immigration policies create conditions of employment exclusion that may negatively influence the health of immigrants. In particular, these policy effects are reflected in labor market and workplace experiences that determine the types of work and employment opportunities that immigrants are able to access and pursue. This study examines the relationship between both cumulative and individual measures of employment exclusion and self-rated health and psychological distress among Asian and Latino immigrants in California, and whether this relationship is modified by legal status.

Compact Yb fiber few-cycle pulse source based on precision pulse compression and shaping with an adaptive fiber Bragg grating.

We generate bandwidth limited 10 µJ pulses of 92 fs pulse width using an adaptive fiber Bragg grating stretcher (FBG) in conjunction with a Lyot filter. The temperature controlled FBG is used to optimize the group delay, whereas the Lyot filter counteracts gain narrowing in the amplifier chain. Soliton compression in a hollow core fiber (HCF) allows for access to the few-cycle pulse regime.

Coherent supercontinuum shaping for multiple wavelength optimization over an octave.

We shape the spectrum of an octave spanning supercontinuum from an erbium fiber laser. The group delay dispersion is controlled through the temperature profile of a chirped fiber Bragg grating. We demonstrate control of spectral broadening, switching in spectral windows, and optimizing power at six wavelengths corresponding to Yb, Ca, and Sr clock transitions, an f-2f pair, and a C-band reference for frequency transfer applications.

Threshold photodissociation dynamics of NO studied by time-resolved cold target recoil ion momentum spectroscopy.

We study the near-threshold photodissociation dynamics of NO by a kinematically complete femtosecond pump-probe scheme using a cold target recoil ion momentum spectrometer. We excite NO to the optically bright ÃB state with a 400 nm pulse and probe the ensuing dynamics via strong field single and double ionization with a 25 fs, 800 nm pulse. The pump spectrum spans the NO(XΠ) + O(P) dissociation channel threshold, and therefore, following internal conversion, excited NO is energetically prepared both "above threshold" (dissociating) and "below threshold" (nondissociating).

Rovibrational quantum state resolution of the C fullerene.

The unique physical properties of buckminsterfullerene, C, have attracted intense research activity since its original discovery. Total quantum state-resolved spectroscopy of isolated C molecules has been of particularly long-standing interest. Such observations have, to date, been unsuccessful owing to the difficulty in preparing cold, gas-phase C in sufficiently high densities.

Dysfunctional cerebral autoregulation is associated with delirium in critically ill adults.

Delirium is common during critical illness and is associated with morbidity and mortality, but its pathophysiology is unknown. We tested whether dysfunctional cerebral autoregulation (CA) contributes to the development of delirium. Adult patients ( = 40) with respiratory failure and/or shock were prospectively enrolled.

Midinfrared frequency comb by difference frequency of erbium and thulium fiber lasers in orientation-patterned gallium phosphide.

We generate over 60 mW of pulses with wavelengths from 6 to 11 micrometers by difference frequency mixing between erbium and thulium fiber amplifiers in orientation-patterned GaP with a photon conversion efficiency of 0.2. By stabilizing the repetition rate of the shared oscillator and adding a frequency shifter to one arm, the output becomes a frequency comb with tunable carrier envelope offset.

Harmonic generation in solids with direct fiber laser pumping.

High harmonic generation in solids presents the possibility for bringing attosecond techniques to semiconductors and a simple source for frequency comb spectroscopy in the vacuum ultraviolet. We generate up to the seventh harmonic of a Tm fiber laser by focusing in silicon or zinc oxide. The harmonics are strong and stable, with no indication of material damage.

Three-photon absorption in optical parametric oscillators based on OP-GaAs.

We report on, to the best of our knowledge, the first singly resonant (SR), synchronously pumped optical parametric oscillator (OPO) based on orientation-patterned gallium arsenide (OP-GaAs). Together with a doubly resonant (DR) degenerate OPO based on the same OP-GaAs material, the output spectra cover 3 to 6 μm within ∼3  dB of relative power. The DR-OPO has the highest output power reported to date from a femtosecond, synchronously pumped OPO based on OP-GaAs.

Fourier transform and Vernier spectroscopy using an optical frequency comb at 3-5.4 μm.

We present a versatile mid-infrared frequency comb spectroscopy system based on a doubly resonant optical parametric oscillator tunable in the 3-5.4 μm range and two detection methods: a Fourier transform spectrometer (FTS) and a continuous-filtering Vernier spectrometer (CF-VS). Using the FTS with a multipass cell, we measure high precision broadband absorption spectra of CH at 3.

Self-referenced, accurate and sensitive optical frequency comb spectroscopy with a virtually imaged phased array spectrometer.

We present a cavity-enhanced direct optical frequency comb spectroscopy system with a virtually imaged phased array (VIPA) spectrometer and either a dither or a Pound-Drever-Hall (PDH) locking scheme used for stable transmission of the comb through the cavity. A self-referenced scheme for frequency axis calibration is shown along with an analysis of its accuracy. A careful comparison between both locking schemes is performed based on near-IR measurements of the carbon monoxide ν=3←0 band P branch transitions in a gas sample with known composition.

Correlated Synaptic Inputs Drive Dendritic Calcium Amplification and Cooperative Plasticity during Clustered Synapse Development.

The mechanisms that instruct the assembly of fine-scale features of synaptic connectivity in neural circuits are only beginning to be understood. Using whole-cell electrophysiology, two-photon calcium imaging, and glutamate uncaging in hippocampal slices, we discovered a functional coupling between NMDA receptor activation and ryanodine-sensitive intracellular calcium release that dominates the spatiotemporal dynamics of activity-dependent calcium signals during synaptogenesis. This developmentally regulated calcium amplification mechanism was tuned to detect and bind spatially clustered and temporally correlated synaptic inputs and enacted a local cooperative plasticity rule between coactive neighboring synapses.

Midinfrared frequency comb from self-stable degenerate GaAs optical parametric oscillator.

We pump a degenerate frequency-divide-by-two optical parametric oscillator (OPO) based on orientation-patterned GaAs with a stable Tm frequency comb at 2 micrometer wavelength and measure the OPO comb offset frequency and linewidth. We show frequency division by two with sub-Hz relative linewidth of the comb teeth. The OPO thermally self-stabilizes and oscillates for nearly an hour without any active control.

A cost-effective method for preparing, maintaining, and transfecting neurons in organotypic slices.

The cellular and molecular mechanisms that underlie brain function are challenging to study in the living brain. The development of organotypic slices has provided a welcomed addition to our arsenal of experimental brain preparations by allowing both genetic and prolonged pharmacological manipulations in a system that, much like the acute slice preparation, retains several core features of the cellular and network architecture found in situ. Neurons in organotypic slices can survive in culture for several weeks, can be molecularly manipulated by transfection procedures and their function can be interrogated by traditional cellular electrophysiological or imaging techniques.

Midinfrared frequency combs from coherent supercontinuum in chalcogenide and optical parametric oscillation.

We observe the coherence of the supercontinuum generated in a nanospike chalcogenide-silica hybrid waveguide pumped at 2 μm. The supercontinuum is shown to be coherent with the pump by interfering it with a doubly resonant optical parametric oscillator (OPO) that is itself coherent with the shared pump laser. This enables coherent locking of the OPO to the optically referenced pump frequency comb, resulting in a composite frequency comb with wavelengths from 1 to 6 μm.

Calcium influx through N-type channels and activation of SK and TRP-like channels regulates tonic firing of neurons in rat paraventricular thalamus.

The thalamus is a major relay and integration station in the central nervous system. While there is a large body of information on the firing and network properties of neurons contained within sensory thalamic nuclei, less is known about the neurons located in midline thalamic nuclei, which are thought to modulate arousal and homeostasis. One midline nucleus that has been implicated in mediating stress responses is the paraventricular nucleus of the thalamus (PVT).

Differential subcellular targeting of glutamate receptor subtypes during homeostatic synaptic plasticity.

Homeostatic processes are believed to contribute to the stability of neuronal networks that are perpetually influenced by Hebbian forms of synaptic plasticity. Whereas the rules governing the targeting and trafficking of AMPA and NMDA subtypes of glutamate receptors during rapid Hebbian LTP have been extensively studied, those that are operant during homeostatic forms of synaptic strengthening are less well understood. Here, we used biochemical, biophysical, and pharmacological approaches to investigate glutamate receptor regulation during homeostatic synaptic plasticity.

Carrier envelope offset frequency of a doubly resonant, nondegenerate, mid-infrared GaAs optical parametric oscillator.

We measure the carrier envelope offset (CEO) frequency of the mid-infrared frequency comb (wavelength tunable between 3 and 6 μm) from a doubly resonant nondegenerate synchronously pumped optical parametric oscillator (SPOPO) as a function of the CEO frequency of the Tm-fiber pump laser. We show that the CEO frequency of the SPOPO signal wave is a linear function of the CEO frequency of the pump laser, with a slope determined by the signal to pump center-frequency ratio.

Tuning into diversity of homeostatic synaptic plasticity.

Neurons are endowed with the remarkable ability to integrate activity levels over time and tune their excitability such that action potential firing is maintained within a computationally optimal range. These feedback mechanisms, collectively referred to as "homeostatic plasticity", enable neurons to respond and adapt to prolonged alterations in neuronal activity by regulating several determinants of cellular excitability. Perhaps the best-characterized of these homeostatic responses involves the regulation of excitatory glutamatergic transmission.

Examining form and function of dendritic spines.

The majority of fast excitatory synaptic transmission in the central nervous system takes place at protrusions along dendrites called spines. Dendritic spines are highly heterogeneous, both morphologically and functionally. Not surprisingly, there has been much speculation and debate on the relationship between spine structure and function.

LIM domain only 4 (LMO4) regulates calcium-induced calcium release and synaptic plasticity in the hippocampus.

The LIM domain only 4 (LMO4) transcription cofactor activates gene expression in neurons and regulates key aspects of network formation, but the mechanisms are poorly understood. Here, we show that LMO4 positively regulates ryanodine receptor type 2 (RyR2) expression, thereby suggesting that LMO4 regulates calcium-induced calcium release (CICR) in central neurons. We found that CICR modulation of the afterhyperpolarization in CA3 neurons from mice carrying a forebrain-specific deletion of LMO4 (LMO4 KO) was severely compromised but could be restored by single-cell overexpression of LMO4.

Strong ligand-protein interactions revealed by ultrafast infrared spectroscopy of CO in the heme pocket of the oxygen sensor FixL.

In heme-based sensor proteins, ligand binding to heme in a sensor domain induces conformational changes that eventually lead to changes in enzymatic activity of an associated catalytic domain. The bacterial oxygen sensor FixL is the best-studied example of these proteins and displays marked differences in dynamic behavior with respect to model globin proteins. We report a mid-IR study of the configuration and ultrafast dynamics of CO in the distal heme pocket site of the sensor PAS domain FixLH, employing a recently developed method that provides a unique combination of high spectral resolution and range and high sensitivity.