Sociopolitical development: A history and overview of a black liberatory approach to youth development.

Sociopolitical development (SPD) is the process by which people come to understand structural oppression and develop the capacity to reform and transform society, combat oppression, and achieve liberation. In this article, we honor and recognize the community-based framework building of Dr. Roderick Watts and his colleagues, scholars of African descent who pioneered SPD. First, we describe the history and evolution of SPD as both stage and process models of development rooted in Black liberation psychology. We then highlight several contributions of SPD to psychology research and practice including the relevance of sociocultural factors; the integration of intersectionality, well-being, and healing; and the role of context. Throughout, we share parts of conversations with several pioneering SPD scholars regarding the importance of this framework to both Black psychology and psychology broadly. We conclude with recommendations for how psychologists can integrate SPD into their research and practice, as one way to challenge anti-Black racism and reimagine youth resistance against racism and oppression. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The 40Ar(d,p)41Ar cross section between 3-7 MeV.

To determine the safety of using argon as a deuteron beam stopping material, the  40Ar(d,p)41Ar cross section was measured at average deuteron energies of 3.6 MeV, 5.5 MeV, and 7.0 MeV using an activation method. A 16-MeV deuteron beam produced by Lawrence Berkeley National Laboratory's 88-Inch Cyclotron was degraded to each energy by nickel foils and the front wall of an aluminum gas chamber. The reduced-energy deuterons were used to activate a sample of natAr gas. After each irradiation, the gas chamber's  41Ar activation was measured with a high-purity germanium detector. The cross sections measured were larger than a previous measurement by ∼40%.

Characterization of photodetector temporal response for neutron time-of-flight (nToF) diagnostics at the National Ignition Facility.

The temporal response of a microchannel plate photomultiplier tube used in the suite of neutron time of flight (nToF) diagnostics at the National Ignition Facility has been characterized to reduce uncertainty in, and understanding of, shot parameters obtained from nTOF data. A short pulse laser, neutral density glass filters, and electrical attenuators were used to gather statistically significant samples of photodetector impulse response functions (IRF) in rapid succession. Individual components have been absolutely calibrated to minimize systematic uncertainties. The zeroth (collected charge), first (transit time), and second central moments (transit time spread) of the IRF were calculated as either the bias voltage or the amount of light incident on the detector was varied. Timing reference was provided by a monitor photodiode viewing a pickoff of the incident laser pulse. The primary sources of uncertainty are jitter in the monitor photodiode and the statistical variation across our measurement period. The spreads in the first moment, with respect to the timing photodiode, and the square root of the second central moment were found to be less than 50 ps and 150 ps, respectively.

Gonadotropin-releasing hormone immunization for the treatment of urethral sphincter mechanism incompetence in ovariectomized bitches.

We have investigated GnRH immunization for the treatment of urethral sphincter mechanism incompetence in ovariectomized bitches. It has been reported that decreasing LH secretion through the use of GnRH agonists temporarily restores continence in some bitches. Therefore, decreasing the circulating LH concentrations by immunizing against GnRH might temporarily maintain continence in incontinent dogs. Sixteen incontinent dogs given phenylpropanolamine (PPA) to control incontinence were recruited for this study. Eleven dogs were immunized against GnRH (novel treatment group) at week 0, and nine dogs were vaccinated again 4 weeks later. Five dogs (standard treatment group) were vaccinated with a placebo twice at 4-week intervals. PPA was discontinued in the novel treatment group 2 weeks after revaccination, and standard-treatment dogs were given PPA for the duration of the study. Blood samples were collected before each treatment and at 6, 8, 10, 12, 16, 20, and 24 weeks and owners recorded episodes of incontinence throughout the study. Ten of the eleven dogs in the novel treatment group experienced side effects as a result of vaccination; two of these dogs experienced more severe side effects after the first vaccination and were withdrawn from the study as a result. Of the nine dogs that completed the vaccination series, four dogs remained continent after PPA was discontinued. For these four dogs, there was no difference in incontinent episodes when they were given PPA versus treatment with the vaccine. All nine novel-treatment dogs developed a GnRH antibody titer and experienced a significant decrease in circulating LH concentrations. In conclusion, GnRH immunization was effective in maintaining continence in four of the nine incontinent ovariectomized dogs, and in these dogs, treatment with the vaccine was comparable with treatment with PPA.

Dielectric polarization, anisotropy and nonradiative energy transfer into nanometre-scale thin semiconducting films.

A common problem of nonradiative energy transfer (NRET) from a small energy donor into a neighbouring energy acceptor layer is addressed with the emphasis on the layer thickness dependence. Two complementary approaches are employed to study dielectric polarization effects on NRET into thin films: a macroscopic analysis treating the acceptor layer as a continuum characterized by a frequency-dependent dielectric function, and a direct modelling utilizing discrete acceptor lattices, each of the acceptors being a polarizable point dipole. Explicit illustrations are provided of an interesting phenomenon, when NRET into thinner films can counter-intuitively be more efficient than NRET into thicker films. We show that this phenomenon may take place for a broad range of the acceptor polarization responses, including metallic-like and insulating behaviour as well as responses with weak and strong dissipation. The spectral vicinity of a strong dielectric resonance in the acceptor layer is studied as a specific example. The role of geometry-derived and intrinsic anisotropy of the acceptor response is clarified in the illustrations. Our results suggest that NRET optimization might be possible in the design of hybrid nanostructures, where the geometry of the structures is better matched with spectral properties of donor and acceptor subsystems.

Dyspepsia in homeless adults.

GOALS: To determine the prevalence of and risk factors for dyspepsia in a representative sample of homeless persons using shelters in Toronto, Canada. BACKGROUND: Homeless people have many risk factors for dyspepsia, but little information is available on gastrointestinal symptoms in this population. STUDY: Cross-sectional survey of a representative sample of 100 homeless adults, with serologic testing for Helicobacter pylori infection. RESULTS: The prevalence of moderate, severe, or very severe symptoms within the past 3 months was 18% for upper stomach pain and 59% for any dyspeptic symptom. Nonwhite ethnicity (odds ratio, 3.5; 95% confidence interval, 1.1-10.9) and a history of gastrointestinal disease (odds ratio, 8.6; 95% confidence interval, 2.5-29.6) were significantly associated with moderate to very severe upper stomach pain. H. pylori infection was identified in 31% of participants but was not significantly associated with dyspepsia. CONCLUSIONS: Dyspepsia is a common problem among homeless adults in Toronto. The presence of upper stomach pain is most strongly associated with a history of gastrointestinal disease.

Probing the structure of Saccharomyces cerevisiae RNase MRP.

In yeast, RNase MRP (mitochondrial RNA processing), a ribonucleoprotein precursor rRNA processing enzyme, possesses one putatively catalytic RNA and ten protein subunits and is highly related to RNase P. Structural analysis of the MRP RNA provides data that closely match a previous secondary-structure model derived from phylogenetic analysis, with the exception of an additional stem. This stem occupies an equivalent position to the P7 stem of RNase P RNA and its inclusion confers on MRP RNA a greater similarity to the core P RNA structure. In vivo studies indicate that the P7-like stem can form, but is not a part of, the active enzyme structure. Stem formation would increase RNA stability in the absence of proteins and our alternative structure may be a valid intermediate species in RNase MRP assembly. Further ongoing studies of this enzyme reveal an extensive network of interactions between subunits and a probable central role for the Pop1, Pop4 and Pop7 subunits.

Quantum thermodynamic cooling cycle.

The quantum-mechanical and thermodynamic properties of a three-level molecular cooling cycle are derived. An inadequacy of earlier models is rectified in accounting for the spontaneous emission and absorption associated with the coupling to the coherent driving field via an environmental reservoir. This additional coupling need not be dissipative, and can provide a thermal driving force-the quantum analog of classical absorption chillers. The dependence of the maximum attainable cooling rate on temperature, at ultralow temperatures, is determined and shown to respect the recently established fundamental bound based on the second and third laws of thermodynamics.

Effects of ketogenic diet on development and behavior: preliminary report of a prospective study.

The ketogenic diet is increasingly used for the management of difficult-to-control seizures in children. Here, we describe the first prospective study of the effects of the diet on development, behavior, and parenting stress. Participants were 65 children (36 males, 29 females) with intractable seizures, ages 18 months to 14 years 6 months, enrolled in a prospective study at the Johns Hopkins Hospital, Baltimore, MD, USA, to study the diet's efficacy. Children were assessed before diet initiation and at 1-year follow-up. At follow-up, 52% (34 of 65) children remained on the diet. Mean seizure frequency decreased from 25 per day before diet initiation to less than two per day 1 year later. At follow-up, mean developmental quotient showed statistically significant improvement (p<0.05), with significant behavioral improvements in attention and social functioning. Parental stress was essentially unchanged. No baseline factor examined predicted diet adherence, and the primary reason for diet discontinuation was insufficient seizure control. These preliminary results support prior anecdotal reports of the beneficial effects of the diet on cognition and behavior.

Congruency in defining critical thinking by nurse educators and non-nurse scholars.

This study investigated nurse educators' definition of the concept critical thinking. A sample of 201 baccalaureate nurse educators in midwest nursing programs completed a questionnaire identifying their perception of critical-thinking skills and characteristics, and their agreement with non-nurse critical-thinking experts on items often considered to be critical thinking. This study found that nurse educators agreed with non-nurse critical-thinking experts on the skills and dispositions; however, significant differences were found between nurse educators and non-nurse experts regarding concepts related to critical thinking. Nurse educators were more likely to identify researching, problem-solving, decision-making, and planning as critical thinking. Despite their assertion otherwise, it is apparent from this study that nurse educators have a different perception of critical thinking than scholars in other disciplines. This study suggests that practice disciplines such as nursing may perceive critical thinking differently than educators in nonpractice disciplines.

Spherical gradient-index lenses as perfect imaging and maximum power transfer devices.

Gradient-index lenses can be viewed from the perspectives of both imaging and nonimaging optics, that is, in terms of both image fidelity and achievable flux concentration. The simple class of gradient-index lenses with spherical symmetry, often referred to as modified Luneburg lenses, is revisited. An alternative derivation for established solutions is offered; the method of Fermat's strings and the principle of skewness conservation are invoked. Then these nominally perfect imaging devices are examined from the additional vantage point of power transfer, and the degree to which they realize the thermodynamic limit to flux concentration is determined. Finally, the spherical gradient-index lens of the fish eye is considered as a modified Luneburg lens optimized subject to material constraints.

Gastrocutaneous fistula in children after removal of gastrostomy tube: incidence and predictive factors.

BACKGROUND/PURPOSE: Removal of a gastrostomy tube may result in a persistent gastrocutaneous fistula. The authors reviewed their experience to determine the incidence of this event in children, and the factors that contribute to its occurrence. METHODS: Over a 3-year period, 32 children had a gastrostomy tube placed that was subsequently removed. Of these, 18 sites closed spontaneously and 14 had a persistent gastrocutaneous fistula (44%). The groups were similar with respect to age, sex, and diagnosis. Mean time from insertion to removal of the tube was 6.5+/-2 months in the group with spontaneous closure, and 29.8+/-8 months in the gastrocutaneous fistula group (P<.05). RESULTS: One of 17 (6%) children who had tubes removed within 8 months of insertion had a fistula, compared with 13 of 15 (87%) of those who had one removed after 9 or more months (P<.001). Patients with tubes inserted percutaneously (PEG) were less likely to have a fistula than those using the Stamm technique (28% v. 55%, not significant), although PEGs also tended to be in place for a shorter time before removal (12.6 v. 21.1 months). Steroids did not increase the likelihood of a fistula (50% v. 42%, not significant). CONCLUSIONS: The incidence of persistent gastrocutaneous fistula is high after gastrostomytube removal in children. The most important factor predisposing to this problem appears to be the length of time the tube is in place before its removal. Almost all tubes removed within 8 months will close spontaneously.

Adjunctive use of a subgingival controlled-release chlorhexidine chip reduces probing depth and improves attachment level compared with scaling and root planing alone.

The present studies evaluated the efficacy of a controlled-release biodegradable chlorhexidine (CHX) (2.5 mg) chip when used as an adjunct to scaling and root planing on reducing probing depth (PD) and improving clinical attachment level (CAL) in adult periodontitis. Two double-blind, randomized, placebo-controlled multi-center clinical trials (5 centers each) were conducted; pooled data are reported from all 10 centers (447 patients). At baseline, following 1 hour of scaling and root planing (SRP) in patients free of supragingival calculus, the chip was placed in target sites with PD 5 to 8 mm which bled on probing. Chip placement was repeated at 3 and/or 6 months if PD remained > or = 5 mm. Study sites in active chip subjects received either CHX chip plus SRP or SRP alone (to maintain study blind). Sites in placebo chip subjects received either placebo chip plus SRP or SRP alone. Examinations were performed at baseline; 7 days; 6 weeks; and 3, 6, and 9 months. At 9 months significant reductions from baseline favoring the chlorhexidine chip compared with both control treatments were observed with respect to PD (chlorhexidine chip plus SRP, 0.95 +/- 0.05 mm; SRP alone, 0.65 +/- 0.05 mm, P < 0.001; placebo chip plus SRP, 0.69 +/- 0.05 mm, P < 0.001) and CAL (chlorhexidine chip plus SRP, 0.75 +/- 0.06 mm; SRP alone, 0.58 +/- 0.06 mm, P < 0.05; placebo chip plus SRP, 0.55 +/- 0.06 mm, P < 0.05). The proportion of patients who evidenced a PD reduction from baseline of 2 mm or more at 9 months was significantly greater in the chlorhexidine chip group (19%) compared with SRP controls (8%) (P < 0.05). Adverse effects were minor and transient toothache, including pain, tenderness, aching, throbbing, soreness, discomfort, or sensitivity was the only adverse effect that was higher in the chlorhexidine group as compared to placebo (P = 0.042). These data demonstrate that the adjunctive use of the chlorhexidine chip results in a significant reduction of PD when compared with both SRP alone or the adjunctive use of a placebo chip. These multi-center randomized control trials suggest that the chlorhexidine chip is a safe and effective adjunctive chemotherapy for the treatment of adult periodontitis.

Reflectors for uniform far-field irradiance: fundamental limits and example of an axisymmetric solution.

We establish a fundamental bound on the field of view over which strictly uniform far-field irradiance can be achieved in symmetric two-dimensional (2D, troughlike) and three-dimensional (3D, conelike) illumination systems. Earlier results derived for particular 2D devices are shown to be special cases of the general formula. For a rotationally symmetric 3D luminaire with a Lambertian disk light source and a prescribed uniform core region half-angle theta(c), no more than tan2(theta(c)) can be projected within a uniform core region. Hence the efficiency with which such illuminators can produce uniform flux is severely limited for many problems of practical interest. Guided by the tailored edge-ray device formalism for the design of 2D luminaires, we develop a 3D reflector that produces extremely uniform far-field illuminance.

Nonimaging optical designs for maximum-power-density remote irradiation.

Designs for flexible, high-power-density, remote irradiation systems are presented. Applications include industrial infrared heating such as in semiconductor processing, alternatives to laser light for certain medical procedures, and general remote high-brightness lighting. The high power densities in herent to the small active radiating regions of conventional metal-halide, halogen, xenon, microwave-sulfur, and related lamps can be restored with nonimaging concentrators with little loss of power. These high fluxlevels can then be transported at high transmissivity with light channels such as optical fibers or lightpipes, and reshaped into luminaires that can deliver prescribed angular and spatial flux distributions onto desired targets. Details for nominally two- and three-dimensional systems are developed, along with estimates ofoptical performance.

Optical performance of axisymmetric edge-ray concentrators and illuminators.

The optical performance of axisymmetric radiation concentrators and illuminators that are derived when two-dimensional edge-ray designs are rotated about their optic axis is investigated. Of particular interest are devices with spherical and cylindrical absorbers or light sources, for which the inherent ray rejection can be substantial. From the principle of etendue (phase-space) conservation, a lower bound for ray rejection can be established. With computer ray tracing, we demonstrate that this bound underestimates the actual ray rejection by only a few percent at most. Hence, to a good approximation, it can be used as an equality in analytic predictions of characteristic efficiency-concentration curves. By designing for absorbers or sources with a bald spot, the full range of efficiency and flux concentration values can be realizedand the trade-off between them can be quantified. The optical performance of these edge-ray designs is also compared against fundamental upper bounds on the flux concentration and efficiency of axisymmetric devices.

Prospective study of esophageal botulinum toxin injection in high-risk achalasia patients.

OBJECTIVES: Intrasphincteric injection of botulinum toxin has been reported as a safer treatment alternative to balloon dilation or myotomy in achalasia. We studied botulinum toxin injection in achalasia patients who are at high surgical risk because of age or concomitant medical problems. METHODS: Consecutive patients who were elderly (age > 60 yr) or who had significant medical problems or both were enrolled after confirming achalasia by history, manometry, and esophageal scintigraphy. Patients underwent esophagogastroduodenoscopy, and 20 units of botulinum toxin were injected into each of four quadrants of the lower esophageal sphincter. Patients were interviewed at 1, 3, 5, and 6 months, and esophageal scintigraphy was repeated at 1 month. RESULTS: Sixteen patients with increased surgical risks were studied: many had serious coronary heart disease, diabetes, or obstructive lung disease. At 1 month, 12 of 16 patients had a clinical response but 5 developed recurrent symptoms within 6 months. One developed reflux, and two were found to have esophageal wall inflammation, loss of tissue planes, and mediastinal adhesions at subsequent myotomy. CONCLUSIONS: Intrasphincteric botulinum toxin injection may be appropriate in those achalasia patients who are elderly or have concomitant medical problems but concern persists regarding the length of the response and untoward side effects.