Are the returns to technological change in health care declining?

Whether the U.S. health care system supports too much technological change—so that new technologies of low value are adopted, or worthwhile technologies become overused—is a controversial question. This paper analyzes the marginal value of technological change for elderly heart attack patients in 1984–1990. It estimates the additional benefits and costs of treatment by hospitals that are likely to adopt new technologies first or use them most intensively. If the overall value of the additional treatments is declining, then the benefits of treatment by such intensive hospitals relative to other hospitals should decline, and the additional costs of treatment by such hospitals should rise. To account for unmeasured changes in patient mix across hospitals that might bias the results, instrumental–variables methods are used to estimate the incremental mortality benefits and costs. The results do not support the view that the returns to technological change are declining. However, the incremental value of treatment by intensive hospitals is low throughout the study period, supporting the view that new technologies are overused.

Abrupt climate change in the computer: Is it real?

Models suggest that dramatic changes in the ocean circulation are responsible for abrupt climate changes during the last ice age and may possibly alter the relative climate stability of the last 10,000 years.

Aeolian dust in Colorado Plateau soils: Nutrient inputs and recent change in source

Aeolian dust (windblown silt and clay) is an important component in arid-land ecosystems because it may contribute to soil formation and furnish essential nutrients. Few geologic surfaces, however, have been characterized with respect to dust-accumulation history and resultant nutrient enrichment. We have developed a combination of methods to identify the presence of aeolian dust in arid regions and to evaluate the roles of this dust in ecosystem processes. Unconsolidated sandy sediment on isolated surfaces in the Canyonlands region of the Colorado Plateau differs greatly in mineralogical and chemical composition from associated bedrock, mainly aeolian sandstone. Detrital magnetite in the surficial deposits produces moderately high values of magnetic susceptibility, but magnetite is absent in nearby bedrock. A component of the surficial deposits must be aeolian to account for the abundance of magnetite, which formed originally in far-distant igneous rocks. Particle-size analysis suggests that the aeolian dust component is typically as much as 20–30%. Dust inputs have enriched the sediments in many elements, including P, Mg, Na, K, and Mo, as well as Ca, at sites where bedrock lacks calcite cement. Soil-surface biologic crusts are effective dust traps that apparently record a change in dust sources over the past several decades. Some of the recently fallen dust may result from human disturbance of land surfaces that are far from the Canyonlands, such as the Mojave Desert. Some land-use practices in the study area have the potential to deplete soil fertility by means of wind-erosion removal of aeolian silt.

Host-parasite dynamics and outgrowth of virus containing a single K70R amino acid change in reverse transcriptase are responsible for the loss of human immunodeficiency virus type 1 RNA load suppression by zidovudine.

The association between human immunodeficiency virus type I (HIV-1) RNA load changes and the emergence of resistant virus variants was investigated in 24 HIV-1-infected asymptomatic persons during 2 years of treatment with zidovudine by sequentially measuring serum HIV-1 RNA load and the relative amounts of HIV-1 RNA containing mutations at reverse transcriptase (RT) codons 70 (K-->R), 41 (M-->L), and 215 (T-->Y/F). A mean maximum decline in RNA load occurred during the first month, followed by a resurgence between 1 and 3 months, which appeared independent of drug-resistance. Mathematical modeling suggests that this resurgence is caused by host-parasite dynamics, and thus reflects infection of the transiently increased numbers of CD4+ lymphocytes. Between 3 and 6 months of treatment, the RNA load returned to baseline values, which was associated with the emergence of virus containing a single lysine to arginine amino acid change at RT codon 70, only conferring an 8-fold reduction in susceptibility. Despite the relative loss of RNA load suppression, selection toward mutations at RT codons 215 and 41 continued. Identical patterns were observed in the mathematical model. While host-parasite dynamics and outgrowth of low-level resistant virus thus appear responsible for the loss of HIV-1 RNA load suppression, zidovudine continues to select for alternative mutations, conferring increasing levels of resistance.

Rapid genome change in synthetic polyploids of Brassica and its implications for polyploid evolution.

Although the evolutionary success of polyploidy in higher plants has been widely recognized, there is virtually no information on how polyploid genomes have evolved after their formation. In this report, we used synthetic polyploids of Brassica as a model system to study genome evolution in the early generations after polyploidization. The initial polyploids we developed were completely homozygous, and thus, no nuclear genome changes were expected in self-fertilized progenies. However, extensive genome change was detected by 89 nuclear DNA clones used as probes. Most genome changes involved loss and/or gain of parental restriction fragments and appearance of novel fragments. Genome changes occurred in each generation from F2 to F5, and the frequency of change was associated with divergence of the diploid parental genomes. Genetic divergence among the derivatives of synthetic polyploids was evident from variation in genome composition and phenotypes. Directional genome changes, possibly influenced by cytoplasmic-nuclear interactions, were observed in one pair of reciprocal synthetics. Our results demonstrate that polyploid species can generate extensive genetic diversity in a short period of time. The occurrence and impact of this process in the evolution of natural polyploids is unknown, but it may have contributed to the success and diversification of many polyploid lineages in both plants and animals.

Do Things Change in Therapy That Are Not Measured By Self-report Instruments?

This study investigates a new way of assessing change in psychotherapy, with the goal of decreasing the schism in the field of psychology between research and clinical practice. Change in psychotherapy was assessed in clients presenting with depressive symptoms who were seeking therapy at the Professional Psychology Center (PPC) at the University of Denver. Prior to beginning treatment, the subjects completed the Beck Depression Inventory- II (BDI-II) and the Symptom Checklist-90-R (SCL-90), and were also assessed by independent clinicians using the Shedler-Westen Assessment Procedure II (SWAP-II). Six to nine months later, after completing at least 12 psychotherapy sessions (range 12-21 sessions), the assessment procedure was repeated.There were no significant differences pre- to post-treatment on any measure. However, two subjects in the sample appeared to benefit from treatment, as assessed by both the self-report measures and the SWAP-II. The findings for these two subjects suggest that the SWAP-II can provide a greater depth of understanding about what can change in therapy than self-report measures alone. Possible reasons for the lack of treatment effects in the larger sample are discussed.

Electroencephalogram based Causality Graph Analysis in Behavior Tasks of Parkinson’s Disease Patients

Electroencephalographic (EEG) signals of the human brains represent electrical activities for a number of channels recorded over a the scalp. The main purpose of this thesis is to investigate the interactions and causality of different parts of a brain using EEG signals recorded during a performance subjects of verbal fluency tasks. Subjects who have Parkinson's Disease (PD) have difficulties with mental tasks, such as switching between one behavior task and another. The behavior tasks include phonemic fluency, semantic fluency, category semantic fluency and reading fluency. This method uses verbal generation skills, activating different Broca's areas of the Brodmann's areas (BA44 and BA45). Advanced signal processing techniques are used in order to determine the activated frequency bands in the granger causality for verbal fluency tasks. The graph learning technique for channel strength is used to characterize the complex graph of Granger causality. Also, the support vector machine (SVM) method is used for training a classifier between two subjects with PD and two healthy controls. Neural data from the study was recorded at the Colorado Neurological Institute (CNI). The study reveals significant difference between PD subjects and healthy controls in terms of brain connectivities in the Broca's Area BA44 and BA45 corresponding to EEG electrodes. The results in this thesis also demonstrate the possibility to classify based on the flow of information and causality in the brain of verbal fluency tasks. These methods have the potential to be applied in the future to identify pathological information flow and causality of neurological diseases.

Patterns and Predictors of Stability and Change in Representations of Romantic Relationships in Adolescence and Young Adulthood

Research on the stability of attachment representations across the lifespan has led to two alternative perspectives: the prototype and revisionist perspectives (Fraley, 2002). The prototype perspective posits that there is a stable factor underlying fluctuations in representations and the revisionist perspective argues that there is no inherently stable factor. The current study employed a latent trait-state model to investigate these alternative models of stability and change in representations of romantic relationships in adolescence and young adulthood. The study also sought to identify individual characteristics and relationship experiences that are associated with changes in representations. In a sample of 200 participants, representations were assessed by interview and self-report over seven measurement occasions between ages 15 and 23. Results were consistent with the prototype perspective emphasizing that a stable, latent factor exerts a consistent influence over the lifespan. In addition to a stable component, representations incorporated a component that varies over time. Findings showed that this fluctuating component of representations was associated with internalizing and externalizing symptomatology as well as experiences of support and negative interaction in relationships.

Luminosity dependent accretion state change in GRO J1008–57

In a former publication, we have analyzed the transient neutron star X-ray binary GRO J1008–57 using all available RXTE-, Swift-, and Suzaku-data. As we have found, the source’s spectral components, i.e., a power-law with high exponential cutoff and a black-body, are strongly correlated with the hard X-ray flux (15–50 keV). We update the analytical description of these dependence, including a change in the photon index behaviour from a flat to a logarithmic function. The flux, where the change occurs, is consistent with the onset of the black-body emission. Thus, a change of the accretion state always occurs in GRO J1008–57 at a particular flux level.

Fine-scale estimations of bioclimatic change in the Valencia region, Spain

Recent advances in statistical downscaling have allowed the reconstruction of temperatures for the complete 1948–2011 period in a spatial resolution of 90 m and without gaps for the Valencian Community (Spain) and bordering areas. It presently enables analyses in this region, which allows the determination of recent temperature changes at subregional and local scales. The present work focuses on obtaining the thermicity index according to Rivas-Martínez, a well-known indicator of different thermotypes associated with bioclimatic horizons. The change in this index, which has happened in the region between 1948 and 2011, was calculated by generating fine-scale maps of the potential extension of different thermotypes. The results show a greater regression for the thermotypes in a finicolous position, e.g. Orotemperate, Supratemperate and Supramediterranean horizons, which herein indicate greater potential vulnerability in climate change. In the absence of, and given the need for, such fine-scale information, this work should be useful for specialized researchers to spatially limit the potentially most vulnerable biotopes to climate change.

An analysis of culture change in the Ackmen-Lowry area / John B. Rinaldo, Assistant, Archaeology.

v.36:no.5(1950)

Ethnogenesis and Craniofacial Change in Japan from the Perspective of Nonmetric Traits

To examine population affinities in light of the ‘dual structure model’, frequencies of 21 nonmetric cranial traits were analyzed in 17 prehistoric to recent samples from Japan and five from continental northeast Asia. Eight bivariate plots, each representing a different bone or region of the skull, as well as cluster analysis of 21-trait mean measures of divergence using multidimensional scaling and additive tree techniques, revealed good discrimination between the Jomon-Ainu indigenous lineage and that of the immigrants who arrived from continental Asia after 300 BC. In Hokkaido, in agreement with historical records, Ainu villages of Hidaka province were least, and those close to the Japan Sea coast were most, hybridized with Wajin. In the central islands, clines were identified among Wajin skeletal samples whereby those from Kyushu most resembled continental northeast Asians, while those from the northernmost prefectures of Tohoku apparently retained the strongest indigenous heritage. In the more southerly prefectures of Tohoku, stronger traces of Jomon ancestry prevailed in the cohort born during the latest Edo period than in the one born after 1870. Thus, it seems that increased inter-regional mobility and gene flow following the Meiji Restoration initiated the most recent episode in the long process of demic diffusion that has helped to shape craniofacial change in Japan.