Quantum-limited optical time transfer for future geosynchronous links.

The combination of optical time transfer and optical clocks opens up the possibility of large-scale free-space networks that connect both ground-based optical clocks and future space-based optical clocks. Such networks promise better tests of general relativity1-3, dark-matter searches4 and gravitational-wave detection5. The ability to connect optical clocks to a distant satellite could enable space-based very long baseline interferometry6,7, advanced satellite navigation8, clock-based geodesy2,9,10 and thousandfold improvements in intercontinental time dissemination11,12. Thus far, only optical clocks have pushed towards quantum-limited performance13. By contrast, optical time transfer has not operated at the analogous quantum limit set by the number of received photons. Here we demonstrate time transfer with near quantum-limited acquisition and timing at 10,000 times lower received power than previous approaches14-24. Over 300 km between mountaintops in Hawaii with launched powers as low as 40 µW, distant sites are synchronized to 320 attoseconds. This nearly quantum-limited operation is critical for long-distance free-space links in which photons are few and amplification costly: at 4.0 mW transmit power, this approach can support 102 dB link loss, more than sufficient for future time transfer to geosynchronous orbits.

Diastereoselective Hydrogenation of Tetrasubstituted Olefins using a Heterogeneous Pt-Ni Alloy Catalyst.

Stereoselective hydrogenation of tetrasubstituted olefins is an attractive method to access compounds with two contiguous stereocenters. However, homogeneous catalysts for enantio- and diastereoselective hydrogenation exhibit low reactivity toward tetrasubstituted olefins due to steric crowding between the ligand scaffold and the substrate. Monometallic heterogeneous catalysts, on the other hand, provide accessible surface active sites for hindered olefins but exhibit unpredictable and inconsistent stereoinduction. In this work, we develop a Pt-Ni bimetallic alloy catalyst that can diastereoselectively hydrogenate unactivated, sterically-bulky tetrasubstituted olefins, utilizing the more oxophilic Ni atoms to adsorb a hydroxyl directing group and direct facially-selective hydrogen addition to the olefin via the Pt atoms. Structure-activity studies on several Pt-Ni compositions underscore the importance of exposing a uniform PtNi alloy surface to achieve high diastereoselectivity and minimize side reactions. The optimized Pt-Ni/SiO2 catalyst exhibits good functional group tolerance and broad scope for tetrasubstituted olefins in a cyclopentene scaffold, generating cyclopentanol products with three contiguous stereocenters. The synthetic utility of the method is demonstrated in a four-step synthesis of (1R,2S)-(+)-cis-methyldihydrojasmonate with high yield and enantiopurity.

Reaction Chemistry at Discrete Organometallic Fragments on Black Phosphorus.

Black phosphorus (bP) is a two-dimensional van der Waals material unique in its potential to serve as a support for single-site catalysts due to its similarity to molecular phosphines, ligands quintessential in homogeneous catalysis. However, there is a scarcity of synthetic methods to install single metal centers on the bP lattice. Here, we demonstrate the functionalization of bP nanosheets with molecular Re and Mo complexes. A suite of characterization techniques, including infrared, X-ray photoelectron and X-ray absorption spectroscopy as well as scanning transmission electron microscopy corroborate that the functionalized nanosheets contain a high density of discrete metal centers directly bound to the bP surface. Moreover, the supported metal centers are chemically accessible and can undergo ligand exchange transformations without detaching from the surface. The steric and electronic properties of bP as a ligand are estimated with respect to molecular phosphines. Sterically, bP resembles tri(tolyl)phosphine when monodentate to a metal center, and bis(diphenylphosphino)propane when bidentate, whereas electronically bP is a σ-donor as strong as a trialkyl phosphine. This work is foundational in elucidating the nature of black phosphorus as a ligand and underscores the viability of using bP as a basis for single-site catalysts.

Perceived impact of COVID-19 on prevention, treatment, harm reduction, and recovery services for opioid use disorder: National survey of local health departments.

Background: US local health departments (LHDs) have faced the COVID-19 pandemic and the opioid epidemic simultaneously. This article investigates the perceived impact of COVID-19 on the continuation of locally available services for addressing opioid use disorder (OUD). Methods: A national survey of US LHDs was conducted from November to December 2020. The survey asked key personnel in LHDs about the availability of OUD services in their jurisdiction, and how COVID-19 impacted such availability (i.e., whether terminated or continued at a reduced, the same, or an increased level after the arrival of COVID-19). Proportions for each impact category were estimated for prevention, treatment, harm reduction, and recovery services. Logistic regression tested for rural-urban and regional differences in perceived service impact. Results: An 11.4% (214 out of 1873) response rate was attained. Of the returned surveys, 187 were used in the analysis. Reported terminations were generally low, especially for treatment services. School-based prevention initiatives had the highest termination rate (17.2%, 95% CI = 11.4-25.1%). Prevention services had the highest proportions for continuing at a reduced level, except for recovery mutual help programs (53.9%, 95% CI = 45.2-62.4%). LHDs reported continuing services at an increased level at a higher frequency than terminating. Notably, 72.2% (95% CI = 62.7-80.0%) continued telehealth/telemedicine options for OUD at an increased level, and 23.8% (95% CI = 17.8-31.1%) and 10.0% (95% CI = 5.7-16.7%) reported doing the same for naloxone distribution and medications for opioid use disorder (MOUD), respectively. More harm reduction services were continued at the same versus at a reduced level. Service continuation differed little between rural-urban LHDs or by region. Conclusions: The impacts of COVID-19 on OUD service availability in LHD jurisdictions may depend on the specific area of opioid response while the long-term consequences of these changes remain unknown.

Local Policy and Programmatic Activity to Address the US Opioid Crisis: A Cross-Sectional Survey of County Governments.

CONTEXT: Despite attention to federal and state governments' response to the US opioid crisis, few studies have systematically examined local governments' role in tackling this problem. OBJECTIVES: To determine what opioid policy and programmatic activities local governments are implementing, which activities are more challenging and require a greater latent ability to implement, and what community, environmental, and institutional factors shape such ability. DESIGN: A cross-sectional survey and multistage sampling procedure. SETTING/PARTICIPANTS: Of all 358 county governments in 5 purposively selected states (Colorado, North Carolina, Ohio, Pennsylvania, and Washington) surveyed, 171 counties (response rate = 47.8%) with complete data on self-reported policy and programmatic activities and predictor variables were eligible for analysis. MAIN OUTCOME MEASURES: Nineteen opioid policy and programmatic activities were analyzed individually and combined into a latent implementation ability index using empirical Bayes means estimates. RESULTS: Item response theory and bivariate analysis were applied. Item response theory estimates suggested that having police officers carry naloxone and establishing a task force of community leaders were easier to implement than more challenging activities such as establishing needle exchanges and allowing arrest alternatives for opioid offenses. Covering individuals' treatment costs was predicted to involve the highest ability. County population size (r = 0.34; 95% confidence interval [CI], 0.20-0.47), population density (r = 0.35; 95% CI, 0.21-0.47), and being a Pennsylvania county (r = 0.45; 95% CI, 0.32-0.56) showed the strongest associations with latent implementation ability. CONCLUSIONS: Counties appear engaged in opioid policy and programmatic activity, although some activities are likely more difficult and may require greater ability to implement than others. More sparsely populated counties appear more disadvantaged in implementing activities for tackling the opioid crisis and may need additional assistance to leverage their ability to build a comprehensive policy and programmatic infrastructure.

Optical timing jitter due to atmospheric turbulence: comparison of frequency comb measurements to predictions from micrometeorological sensors.

During propagation through atmospheric turbulence, variations in the refractive index of air cause fluctuations in the time-of-flight of laser light. These timing jitter fluctuations are a major noise source for precision laser ranging, optical time transfer, and long-baseline interferometry. While there exist models that estimate the turbulence-induced timing jitter power spectra using parameters obtainable from conventional micrometeorological instruments, a direct and independent comparison of these models to measured timing jitter data has not been done. Here we perform this comparison, measuring turbulence-induced optical pulse timing jitter over a horizontal, near-ground path using frequency comb lasers while independently characterizing the turbulence along the path using a suite of micrometeorological sensors. We compare the power spectra of measured optical pulse timing jitter to predictions based on the measured micrometeorological data and standard turbulence theory. To further quantitatively compare the frequency comb data to the micrometeorological measurements, we extract and compare the refractive index structure parameter, Cn2, from both systems and find agreement to within a factor of 5 for wind speed >1 m/s, and further improvement is possible as wind speed increases. These results validate the use of conventional micrometeorological instruments in predicting optical timing jitter statistics over co-located laser beam paths.

Explaining illness with evil: pathogen prevalence fosters moral vitalism.

Pathogens represent a significant threat to human health leading to the emergence of strategies designed to help manage their negative impact. We examined how spiritual beliefs developed to explain and predict the devastating effects of pathogens and spread of infectious disease. Analysis of existing data in studies 1 and 2 suggests that moral vitalism (beliefs about spiritual forces of evil) is higher in geographical regions characterized by historical higher levels of pathogens. Furthermore, drawing on a sample of 3140 participants from 28 countries in study 3, we found that historical higher levels of pathogens were associated with stronger endorsement of moral vitalistic beliefs. Furthermore, endorsement of moral vitalistic beliefs statistically mediated the previously reported relationship between pathogen prevalence and conservative ideologies, suggesting these beliefs reinforce behavioural strategies which function to prevent infection. We conclude that moral vitalism may be adaptive: by emphasizing concerns over contagion, it provided an explanatory model that enabled human groups to reduce rates of contagious disease.

Comparing Optical Oscillators across the Air to Milliradians in Phase and 10

We demonstrate carrier-phase optical two-way time-frequency transfer (carrier-phase OTWTFT) through the two-way exchange of frequency comb pulses. Carrier-phase OTWTFT achieves frequency comparisons with a residual instability of 1.2×10^{-17} at 1 s across a turbulent 4-km free space link, surpassing previous OTWTFT by 10-20 times and enabling future high-precision optical clock networks. Furthermore, by exploiting the carrier phase, this approach is able to continuously track changes in the relative optical phase of distant optical oscillators to 9 mrad (7 as) at 1 s averaging, effectively extending optical phase coherence over a broad spatial network for applications such as correlated spectroscopy between distant atomic clocks.

Speed-dependent Voigt lineshape parameter database from dual frequency comb measurements at temperatures up to 1305 K. Part II: Argon-broadened H2O absorption, 6801-7188 cm-1.

We report argon-broadened water vapor transition parameters and their temperature dependence based on measured spectra spanning 6801-7188 cm-1 from a broad-bandwidth, high-resolution dual frequency comb spectrometer. The 25 collected spectra of 2% water vapor in argon ranged from 296 K to 1305 K with total pressure spanning 100 Torr to 600 Torr. A multispectrum fitting routine was used in conjunction with a quadratic speed-dependent Voigt profile to extract broadening and shift parameters, and a power-law temperature-dependence exponent for both. The measurements represent the first broad bandwidth, argon-broadened water vapor absorption study, and are an important step toward a foreign-gas-perturbed, high-temperature database developed using advanced lineshape profiles.

Speed-dependent Voigt lineshape parameter database from dual frequency comb measurements up to 1305 K. Part I: Pure H2O absorption, 6801-7188 cm-1.

We measure speed-dependent Voigt lineshape parameters with temperature-dependence exponents for several hundred spectroscopic features of pure water spanning 6801-7188 cm-1. The parameters are extracted from broad bandwidth, high-resolution dual frequency comb absorption spectra with multispectrum fitting techniques. The data encompass 25 spectra ranging from 296 K to 1305 K and 1 to 17 Torr of pure water vapor. We present the extracted parameters, compare them to published data, and present speed-dependence, self-shift, and self-broadening temperature-dependent parameters for the first time. Lineshape data is extracted using a quadratic speed-dependent Voigt profile and a single self-broadening power law temperature-dependence exponent over the entire temperature range. The results represent an important step toward a new high-temperature database using advanced lineshape profiles.

Identity fusion "in the wild": Moving toward or away from a general theory of identity fusion?

Whitehouse's focus on two causes of identity fusion (evolution and shared experiences/biology) deepens understanding of these specific topics. While we applaud his analysis, in his efforts to elaborate these two causes, he has - perhaps unavoidably - produced a narrower conceptualization of identity fusion. This is unfortunate because it undermines his stated goal of developing a more general, encompassing theory.

Brothers in arms: Libyan revolutionaries bond like family.

What motivates ordinary civilians to sacrifice their lives for revolutionary causes? We surveyed 179 Libyan revolutionaries during the 2011 conflict in Libya. These civilians-turned-fighters rejected Gaddafi's jamahiriyya (state of the masses) and formed highly cohesive fighting units typical of intense conflicts. Fighters reported high levels of "identity fusion"--visceral, family-like bonds between fighters and their battalions. Fusion of revolutionaries with their local battalions and their own families were extremely high, especially relative to Libyans who favored the revolution but did not join battalions. Additionally, frontline combatants were as strongly bonded to their battalion as they were to their own families, but battalion members who provided logistical support were more fused with their families than battalions. Together, these findings help illuminate the social bonds that seem to motivate combatants to risk their lives for the group during wartime.

Accurate frequency referencing for fieldable dual-comb spectroscopy.

We describe a dual-comb spectrometer that can operate independently of laboratory-based rf and optical frequency references but is nevertheless capable of ultra-high spectral resolution, high SNR, and frequency-accurate spectral measurements. The instrument is based on a "bootstrapped" frequency referencing scheme in which short-term optical phase coherence between combs is attained by referencing each to a free-running diode laser, whilst high frequency resolution and long-term accuracy is derived from a stable quartz oscillator. The sensitivity, stability and accuracy of this spectrometer were characterized using a multipass cell. We demonstrate comb-resolved spectra spanning from 140 THz (2.14 µm, 4670 cm-1) to 184 THz (1.63 µm, 6140 cm-1) in the near infrared with a frequency sampling of 200 MHz (0.0067 cm-1) and ~1 MHz frequency accuracy. High resolution spectra of water and carbon dioxide transitions at 1.77 µm, 1.96 µm and 2.06 µm show that the molecular transmission acquired with this system operating in the field-mode did not deviate from those measured when it was referenced to a maser and cavity-stabilized laser to within 5.6 × 10-4. When optimized for carbon dioxide quantification at 1.60 µm, a sensitivity of 2.8 ppm-km at 1 s integration time, improving to 0.10 ppm-km at 13 minutes of integration time was achieved.

Differentiated selves can surely be good for the group, but let's get clear about why.

We applaud the goal of reconciling the self and group literatures and agree that a differentiated self may sometimes improve group outcomes. Nevertheless, greater precision regarding the underlying mechanisms is needed. Specifically, differentiated selves improve outcomes by overriding selfishness when they allow for personal regulation (being personally recognized and valued) rather than social regulation (specialization of labor).

Broadband Phase Spectroscopy over Turbulent Air Paths.

Broadband atmospheric phase spectra are acquired with a phase-sensitive dual-frequency-comb spectrometer by implementing adaptive compensation for the strong decoherence from atmospheric turbulence. The compensation is possible due to the pistonlike behavior of turbulence across a single spatial-mode path combined with the intrinsic frequency stability and high sampling speed associated with dual-comb spectroscopy. The atmospheric phase spectrum is measured across 2 km of air at each of the 70,000 comb teeth spanning 233 cm(-1) across hundreds of near-infrared rovibrational resonances of CO(2), CH(4), and H(2)O with submilliradian uncertainty, corresponding to a 10(-13) refractive index sensitivity. Trace gas concentrations extracted directly from the phase spectrum reach 0.7 ppm uncertainty, demonstrated here for CO(2). While conventional broadband spectroscopy only measures intensity absorption, this approach enables measurement of the full complex susceptibility even in practical open path sensing.

Fusion with the Cross-Gender Group Predicts Genital Sex Reassignment Surgery.

Transsexuals vary in the sacrifices that they make while transitioning to their cross-gender group. We suggest that one influence on the sacrifices they make is identity fusion. When people fuse with a group, a visceral and irrevocable feeling of oneness with the group develops. The personal self (the sense of "I" and "me") remains potent and combines synergistically with the social self to motivate behavior. We hypothesized that transsexuals who felt fused with the cross-gender group would be especially willing to make sacrifices while transitioning to that group. Our sample included 22 male-to-female (MtF) and 16 female-to-male (FtM) transsexuals. Consistent with expectation, those who were fused with their cross-gender group (1) expressed more willingness to sacrifice close relationships in the process of changing sex than non-fused transsexuals and (2) actually underwent irreversible surgical change of their primary sexual characteristics (vaginoplasty for MtF transsexuals and hysterectomy for FtM transsexuals). These outcomes were not predicted by a measure of "group identification," which occurs when membership in the group eclipses the personal self (the "I" and "me" is subsumed by the group; in the extreme case, brainwashing occurs). These findings confirm and extend earlier evidence that identity fusion is uniquely effective in tapping a propensity to make substantial sacrifices for the group. We discuss identity fusion as a social psychological determinant of the choices of transsexuals.

Time-domain stabilization of carrier-envelope phase in femtosecond light pulses.

We report a time-domain method of stabilizing the carrier-envelope phase (CEP) of femtosecond pulses. Temporal variations of the pulse envelope and the carrier electric-field phase were separately detected with the aid of intensity cross-correlation and interferometric cross-correlation. These detected signals were used to stabilize the CEP; the resulting 50-fold improvement in the fractional stability of the carrier-envelop-offset frequency was evaluated as 1.2 × 10(-11) at 0.1 second averaging periods and 1.7 × 10(-9) at 80 seconds, corresponding to a carrier envelope phase noise of 75 microradians and 10 milliradians, respectively. This method can be realized with a low pulse energy of ~10 pJ and does not require subsequent power amplification or spectral broadening. The high efficiency and short-term stability of this method can facilitate the use of femtosecond lasers in the field of industrial surface measurements, telecommunications, and space sciences.

Speckle phase noise in coherent laser ranging: fundamental precision limitations.

Frequency-modulated continuous-wave laser detection and ranging (FMCW LADAR) measures the range to a surface through coherent detection of the backscattered light from a frequency-swept laser source. The ultimate limit to the range precision of FMCW LADAR, or any coherent LADAR, to a diffusely scattering surface will be determined by the unavoidable speckle phase noise. Here, we demonstrate the two main manifestations of this limit. First, frequency-dependent speckle phase noise leads to a non-Gaussian range distribution having outliers that approach the system range resolution, regardless of the signal-to-noise ratio. These outliers are reduced only through improved range resolution (i.e., higher optical bandwidths). Second, if the range is measured during a continuous lateral scan across a surface, the spatial pattern of speckle phase is converted to frequency noise, which leads to additional excess range uncertainty. We explore these two effects and show that laboratory results agree with analytical expressions and numerical simulations. We also show that at 1 THz optical bandwidth, range precisions below 10 µm are achievable regardless of these effects.

Facilitators and barriers to adopting or expanding medications for opioid use disorder provision in rural Colorado jails: a qualitative analysis.

BACKGROUND: Opioid use disorder (OUD) is common among individuals who are incarcerated. However, OUD treatment services are sparse in smaller county jails found in many rural areas, which limits a healthy and supportive jail environment. This study assesses the facilitators of and barriers to medications for opioid use disorder (MOUD) adoption or expansion in rural Colorado jails. A qualitative descriptive design was implemented during the summer of 2022 using semi-structured interviews with jail staff, sheriffs, and contracted personnel. Interview questions focused on facilitators of existing MOUD services and barriers to adopting or expanding services. To identify the facilitators and barriers, data were coded using thematic analysis. RESULTS: Seven jails were included in the study. Representatives from each jail participated in the seven interviews, which often included multiple participants per interview. Three of the jails had established routine practices for MOUD administration. Two jails occasionally administered MOUD or had plans in place to be able to administer, while the remaining two did not offer any MOUD. While administrative support, collaborative partnerships, and jail nurses facilitated MOUD use, barriers were more prevalent, including physical space limitations, distance to services, lack of providers in the area, staffing and training issues, funding/budget issues, and perceived risk of diversion. CONCLUSION: Making MOUD available to people who are incarcerated is an important and timely step in enhancing the jail environment, especially in rural areas that often lack access to MOUD. As states look to require MOUD availability for people who are incarcerated, facilitators to MOUD adoption/expansion can be leveraged while strategies are needed to overcome barriers.

Feeling understood fosters identity fusion.

If the consequences of identity fusion are well established, its psychological antecedents are not. To address this shortcoming, eight studies tested the hypothesis that self-verification (receiving evaluations that confirm one's self-views) increases fusion (a synergistic union with a group, individual, or cause), which, in turn, increases behavioral support for the target of fusion. Correlational studies showed that perceived self-verification was positively associated with fusion, which was positively associated with willingness to fight and die for a group (Study 1a), a value (Study 1b), and a leader (Study 1c). Study 2 revealed that increasing perceived self-verification fostered greater willingness to fight and die for the group but only indirectly through increases in fusion. Study 3 showed that 4 months after indicating the degree of fusion with a group, increasing perceived self-verification augmented endorsement of fighting and dying for the group indirectly through elevations in fusion. In Study 4, relational ties mediated the relationship between perceived self-verification and fusion. Finally, face-to-face interviews with incarcerated members of street gangs and organized crime gangs (Studies 5a-5b) showed that perceived self-verification was positively associated with fusion, which was positively associated with sacrifices for the gang (replicating Studies 1a-1c). No evidence emerged supporting a rival causal path in which fusion caused willingness to fight and die through perceived self-verification. Implications for related theoretical approaches and for conceptualizing the relationship between personal identities, social identities, and group processes are discussed. (PsycInfo Database Record (c) 2024 APA, all rights reserved).