Do attentional focus cues affect the type or number of explicit rules? Proof of concepts of the self-invoking trigger or explicit knowledge hypotheses.

Internal focus has been shown to be detrimental to performance by disrupting the motor system, whereas external focus enhances performance by promoting automaticity. One hypothesis, which explains the underlying mechanism of the disruption of the motor system, proposes that internal focus affects the type of thoughts (explicit rules) by invoking self-conscious, evaluative thoughts (McKay et al., 2015). In contrast, another hypothesis proposes that internal focus increases the number of explicit rules, loading working memory (Poolton et al., 2006). To examine the competing hypotheses, neurotypical young adults (22.98 ± 4.46 years old, n = 20 males, n = 40 females) were assigned to one of three groups: external focus (n = 20), internal focus (n = 20), and control (n = 20) groups, and practiced a reciprocal aiming task for two days with retention/transfer tests. Between trials, participant's thoughts were evaluated by an open-ended questionnaire. The type of explicit rules was analyzed using a chi-square test, and the number of explicit rules was analyzed using a mixed-effect Poisson regression. The results showed that external focus resulted in a greater proportion of explicit rules about the task and a lesser proportion of self-evaluative thoughts. The number of explicit rules did not differ between groups. Our results suggest that external focus may strengthen focus on task-relevant features, while internal focus moves people's attention away from important features, potentially explaining why the motor system is disrupted by internal focus.

An evolutionary epigenetic clock in plants.

Molecular clocks are the basis for dating the divergence between lineages over macroevolutionary timescales (~105 to 108 years). However, classical DNA-based clocks tick too slowly to inform us about the recent past. Here, we demonstrate that stochastic DNA methylation changes at a subset of cytosines in plant genomes display a clocklike behavior. This "epimutation clock" is orders of magnitude faster than DNA-based clocks and enables phylogenetic explorations on a scale of years to centuries. We show experimentally that epimutation clocks recapitulate known topologies and branching times of intraspecies phylogenetic trees in the self-fertilizing plant Arabidopsis thaliana and the clonal seagrass Zostera marina, which represent two major modes of plant reproduction. This discovery will open new possibilities for high-resolution temporal studies of plant biodiversity.

An evolutionary epigenetic clock in plants.

Molecular clocks are the basis for dating the divergence between lineages over macro-evolutionary timescales (~10 5 -10 8 years). However, classical DNA-based clocks tick too slowly to inform us about the recent past. Here, we demonstrate that stochastic DNA methylation changes at a subset of cytosines in plant genomes possess a clock-like behavior. This 'epimutation-clock' is orders of magnitude faster than DNA-based clocks and enables phylogenetic explorations on a scale of years to centuries. We show experimentally that epimutation-clocks recapitulate known topologies and branching times of intra-species phylogenetic trees in the selfing plant A. thaliana and the clonal seagrass Z. marina , which represent two major modes of plant reproduction. This discovery will open new possibilities for high-resolution temporal studies of plant biodiversity.

Activation of the VMO and VL during dynamic mini-squat exercises with and without isometric hip adduction.

OBJECTIVE: the purpose of this study was to compare vastus medialis obliquus (VMO) and vastus lateralis (VL) activity while performing a mini-squat with and without isometric hip adduction. DESIGN AND SETTING: a repeated measures within subjects design was used. Subjects performed two sets of three repetitions of a traditional mini-squat and a mini-squat with concurrent hip adduction (squeeze). SUBJECTS: 20 recreationally active subjects (10 men, 10 women age=28.10+/-5.91 years, height=170.94+/-11.03 cm, mass=72.32+/-16.66 kg) with no history of patellofemoral pain (PFP), quadriceps injury, or other knee injury participated in the study. MEASUREMENTS: the EMG signal of the VMO and VL was recorded bilaterally during both exercises. EMG data were normalized to the maximal voluntary isometric contraction (MVIC) of the quadriceps produced during seated, isometric knee extension. RESULTS: results of repeated measures ANOVA's revealed that the squeeze squat produced significantly greater VMO and VL activity than the traditional squat (p=0.02). For both the traditional and squeeze squats, intrasession reliability from the first to the second set was calculated using intraclass correlation coefficient (ICC) formula (3:1) bilaterally for both the VMO and the VL. All ICC values were greater than 0.9. CONCLUSION: combining isometric hip adduction with a mini-squat exercise significantly increases the activity of the quadriceps. Performing mini-squats with isometric hip adduction will be beneficial to patellofemoral patients as they increase quadriceps activity, however, based on our data we cannot conclude that this exercise preferentially recruits the VMO. Further research is needed to determine the exact mechanism by which quadriceps function is altered.

Incidence and management of esophageal stricture formation, ulcer bleeding, perforation, and massive hematoma formation from sclerotherapy versus band ligation.

OBJECTIVES: The aim of this study was to compare the incidence and endoscopic management of esophageal stricture formation, significant ulcer bleeding, massive esophageal hematoma, and perforation resulting from endoscopic band ligation or sclerotherapy of esophageal varices. METHODS: Consecutive esophagogastroduodenoscopies in which band ligation or sclerotherapy was performed for acute or obliterative therapy were entered into a computerized endoscopy database during a 7-yr period. Patients were excluded if they died within 72 h of treatment session from complications unrelated to the procedure. Sclerotherapy was performed using a 25-gauge needle with 1.5% sodium tetradecyl sulfate and banding was primarily performed with a Wilson-Cook 6 or 10 shooter. Complications were assessed at scheduled endoscopy and outpatient clinic visits, review of quality assurance data tallied on a monthly basis, and patient records. RESULTS: Two hundred twenty-one cases of sclerotherapy were performed in 59 patients compared to 110 cases of band ligation in 52 patients. Five patients were excluded because of death within 72 h of the procedure. The incidence of complications from sclerotherapy:banding on a per patient basis included: esophageal stricture formation 25.6%:1.9%, ulcer bleed 25.4%:5.7%, esophageal perforation 2.2%:0%, and massive esophageal hematoma 1.6%:0%. A significant difference in complications between sclerotherapy and band ligation was noted for both stricture formation (p < 0.0005) and ulcer bleeding (p < 0.0001). The majority of ulcer bleeds required no therapeutic intervention, whereas stricture formation required multiple dilation sessions. CONCLUSIONS: Band ligation has a significantly lower incidence of stricture formation and ulcer bleeding compared to sclerotherapy. The majority of complications can be managed with endoscopic interventions.

Caring for the critically ill patient. Current and projected workforce requirements for care of the critically ill and patients with pulmonary disease: can we meet the requirements of an aging population?

CONTEXT: Two important areas of medicine, care of the critically ill and management of pulmonary disease, are likely to be influenced by the aging of the US population. OBJECTIVE: To estimate current and future requirements for adult critical care and pulmonary medicine physicians in the United States. DESIGN, SETTING, AND PARTICIPANTS: Analysis of existing population, patient, and hospital data sets and prospective, nationally representative surveys of intensive care unit (ICU) directors (n = 393) and critical care specialists (intensivists) and pulmonary specialists (pulmonologists) (n = 421), conducted from 1996 to 1999. MAIN OUTCOME MEASURES: Influence of patient, physician, regional, hospital, and payer characteristics on current practice patterns; forecasted future supply of and demand for specialist care through 2030. Separate models for critical care and pulmonary disease. Base-case projections with sensitivity analyses to estimate the impact of future changes in training and retirement, disease prevalence and management, and health care reform initiatives. RESULTS: In 1997, intensivists provided care to 36.8% of all ICU patients. Care in the ICU was provided more commonly by intensivists in regions with high managed care penetration. The current ratio of supply to demand is forecast to remain in rough equilibrium until 2007. Subsequently, demand will grow rapidly while supply will remain near constant, yielding a shortfall of specialist hours equal to 22% of demand by 2020 and 35% by 2030, primarily because of the aging of the US population. Sensitivity analyses suggest that the spread of current health care reform initiatives will either have no effect or worsen this shortfall. A shortfall of pulmonologist time will also occur before 2007 and increase to 35% by 2020 and 46% by 2030. CONCLUSIONS: We forecast that the proportion of care provided by intensivists and pulmonologists in the United States will decrease below current standards in less than 10 years. While current health care reform initiatives and modification of existing practice patterns may temporarily forestall this problem, most anticipated effects are minor in comparison with the growing disease burden created by the aging US population. JAMA. 2000;284:2762-2770.

Immunohistochemical identification of the cytoskeletal elements in the notochord cells of bony fishes.

The medulla of the unconstricted notochords of the shortnose sturgeon, Acipenser brevirostratus, and African lungfish, Protopterus annectens, and the cellular component of the intervertebral joint tissue of the teleost fish, Perca flavescens, are comprised of cells with a large central vacuole. Previous studies on the fine structure of this tissue revealed that the cytoplasm surrounding these vacuoles consists of 10-nm-diameter intermediate filaments. Since in mammals there are a large number of tissue-specific types of intermediate filaments, this study uses antibodies to mammalian intermediate filaments to determine the type of filaments present in the notochord cells of bony fishes. Positive labeling using a polyclonal antibody to human skin keratins is observed in the cytoplasm of the notochord cells in the intervertebral tissues of Perca. These tissues are also probed with the AE series antibodies that label keratins found in mammalian epithelial cells. In both Protopterus and Acipenser the peripheral cytoplasm of the notochord cells is labeled with all three AE antibodies. In Perca only the AE3 antibody probe produces positive staining. These staining patterns are consistent with previous studies on the localization of cytokeratins in fish tissues and indicate that the intermediate filaments in the notochord cells of bony fishes are immunologically similar to the mammalian keratins.

Examination of balance measures produced by the biodex stability system.

OBJECTIVE: Our purpose was to establish normal patterns and relationships of stability using the Biodex Stability System. DESIGN AND SETTING: The design of this study used both nonexperimental and quasi-experimental methods. All testing was performed in a university sports medicine laboratory. SUBJECTS: Nineteen healthy subjects (8 males, 11 females, age = 24.4 +/- 4.2 years; wt = 70.5 +/- 20 kg; ht = 171.2 +/- 11.7 cm) with no history of lower extremity injury participated in this study. MEASUREMENTS: For data analysis, the medial/lateral stability index (MLSI), anterior/posterior stability index (APSI), overall stability index (OSI), and time-in-balance scores were recorded. RESULTS: Multiple regression revealed that APSI and MLSI significantly contributed to the OSI, with the APSI accounting for 95% of the OSI variance. Additionally, the percentage of time spent between 0 degrees and 5 degrees from level was significantly greater than the time spent between 6 degrees and 10 degrees , 11 degrees and 15 degrees , and 16 degrees and 20 degrees . Furthermore, the percentage of time spent between 6 degrees and 10 degrees was significantly greater than the time spent between 16 degrees and 20 degrees . CONCLUSIONS: These data suggest that uninjured individuals spent the majority of the time balanced within 0 degrees to 5 degrees from level and progressively less time at greater angles. Additionally, the data suggest that the OSI is very closely related to the APSI and receives a relatively small contribution from the MLSI. Because of this small contribution, if the clinician is interested in both anterior-posterior and medial-lateral motions, it may be best to use the MLSI and APSI separately rather than the OSI.

Ultrastructure and function of cellular components of the intercentral joint in the percoid vertebral column.

The intervertebral joint of the teleost, Perca flavescens, is formed by opposing amphicoelus centra whose rims are connected by external ligaments. The tissue, located within the space formed by these structures, is derived from the notochord and consists of the elastic externa, the fibrous sheath, and the notochordal cells. The cellular tissue within the joint has many characteristics of a stratified epithelium, and when examined with the transmission electron microscope, at least three morphologically distinct regions can be recognized. First, a peripheral single layer of columnar to squamous-shaped cells lies on a basement membrane immediately deep to the fibrous sheath. Second, several layers of cells, each containing a large central vacuole, occur. Third, in the deepest part of the joint, several layers of attenuated cells surround intracentral fluid-filled lacunae and form a transverse septum across the joint. All cells in this tissue are interconnected by numerous desmosomes. Further, an extensive intermediate filament network exists in all three types of cells. The intermediate filament network in the vacuolated cells is arranged cortically around a membrane-bound vacuole, and suggests that these cells may act as passive cellular hydrostats. The squamous cells surrounding the joint lacunae are structurally similar to mammalian epidermal cells, and the intermediate filament network within them is layered parallel to the surface of the lacunae. The organization of these cells suggests that they are the tensile component of extracellular hydrostats within the intercentral joint. These cellular and extracellular hydrostats within the intercentral joint would function to resist the compressive and tensile stresses encountered during undulatory swimming.

Contemplating home health PPS: current patterns of Medicare service use.

Implementing a per-episode prospective payment system (PPS) for home health services is one option for Medicare policy makers facing rapid increases in service use and expenditures. Analysis of data on recent episodes of Medicare home health care identified systematic differences in service patterns across provider types; these indicate potential differences in the capacity of agencies of different types to adjust to PPS. The second phase of a national demonstration, which is about to be implemented, will provide information on the extent to which the agency practices that generate much of the observed variation (such as the number of visits provided per episode) are susceptible to management decisions; and whether managers can and do respond to the incentives of per-episode prospective payment.

Effects of state prospective reimbursement programs on hospital mortality.

Prospective reimbursement (PR) programs were implemented in a number of states in the 1970s to reduce the rate of inflation in hospital costs. The associated savings have prompted concern about whether hospital administrators have been able to economize in ways that do not compromise patient care. This study examined the effects of PR on hospital mortality in 15 states. A quasi-experimental design was used to compare the 10-year trend in standardized mortality rates in hospitals in these states with those in a national sample of hospitals not receiving PR. Although the introduction of PR was associated with higher mortality on all patient groups studied, there was no indication that the level of cost saving in states under PR was correlated with patterns of mortality rates. We conclude that policymakers must be concerned that PR may be compromising the quality of patient care in hospitals, and that more definitive research is needed to improve understanding of the implied trade-off between cost containment and patient outcomes.