1,549 research outputs found

    Detection of fixed points in spatiotemporal signals by clustering method

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    We present a method to determine fixed points in spatiotemporal signals. A 144-dimensioanl simulated signal, similar to a Kueppers-Lortz instability, is analyzed and its fixed points are reconstructed.Comment: 3 pages, 3 figure

    Quantitative pharmacologic MRI: Mapping the cerebral blood volume response to cocaine in dopamine transporter knockout mice

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    The use of pharmacologic MRI (phMRI) in mouse models of brain disorders allows noninvasive in vivo assessment of drug-modulated local cerebral blood volume changes (ΔCBV) as one correlate of neuronal and neurovascular activities. In this report, we employed CBV-weighted phMRI to compare cocaine-modulated neuronal activity in dopamine transporter (DAT) knockout (KO) and wild-typemice. Cocaine acts to block the dopamine, norepinephrine, and serotonin transporters (DAT, NET, and SERT) that clear their respective neurotransmitters from the synapses, helping to terminate cognate neurotransmission. Cocaine consistently reduced CBV, with a similar pattern of regional ΔCBV in brain structures involved inmediating reward in both DAT genotypes. The largest effects (−20% to −30% ΔCBV) were seen in the nucleus accumbens and several cortical regions. Decreasing response amplitudes to cocaine were noted in more posterior components of the cortico-mesolimbic circuit. DAT KO mice had significantly attenuated ΔCBV amplitudes, shortened times to peak response, and reduced response duration in most regions. This study demonstrates that DAT knockout does not abolish the phMRI responses to cocaine, suggesting that adaptations to loss of DAT and/or retained cocaine activity in other monoamine neurotransmitter systems underlie these responses in DAT KO mice

    Reconstructing palaeotemperatures using leaf floras – case studies for a comparison of leaf margin analysis and the coexistence approach

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    AbstractIn the past the problems and advantages of the nearest-living-relative (NLR) and leaf physiognomy approaches have been repeatedly discussed and it has been demonstrated that both approaches frequently show broad agreement with each other. However, detailed comparisons of the various methods for accuracy in estimation of palaeoclimate at individual localities are still lacking. Such studies are needed before data obtained from different approaches can be integrated in palaeoclimate maps and models. Moreover, there are some indications that leaf physiognomy and NLR approaches may lead to different results. In this study we applied a physiognomic method based on leaf margin analysis and the coexistence approach, a recent variation of the NLR approach, to two Tertiary palaeofloras (Schrotzburg, Middle Miocene, south Germany; Kleinsaubernitz, Upper Oligocene, east Germany). We demonstrated that both approaches can produce reasonable and consistent results if the standard error of the leaf physiognomy palaeoclimate data is taken into account. However, our results and interpretations indicate that reconstructions based on leaf physiognomy are influenced by factors not related to climate, such as sample size and differential preservation or transport. In contrast, reconstructions for the same fossil assemblages based on the coexistence approach seem to be less affected by taphonomic variables, but may be less sensitive to minor climate changes

    Development of forest structure and leaf area in secondary forests regenerating on abandoned pastures in Central Amazonia

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    The area of secondary forest (SF) regenerating from pastures is increasing in the Amazon basin; however, the return of forest and canopy structure following abandonment is not well understood. This study examined the development of leaf area index (LAI), canopy cover, aboveground biomass, stem density, diameter at breast height (DBH), and basal area ( BA) by growth form and diameter class for 10 SFs regenerating from abandoned pastures. Biomass accrual was tree dominated, constituting >= 94% of the total measured biomass in all forests abandoned >= 4 to 6 yr. Vine biomass increased with forest age, but its relative contribution to total biomass decreased with time. The forests were dominated by the tree Vismia spp. (> 50%). Tree stem density peaked after 6 to 8 yr ( 10 320 stems per hectare) before declining by 42% in the 12- to 14-yr-old SFs. Small-diameter tree stems in the 1-5-cm size class composed > 58% of the total stems for all forests. After 12 to 14 yr, there was no significant leaf area below 150-cm height. Leaf area return (LAI = 3.2 after 12 to 14 yr) relative to biomass was slower than literature-reported recovery following slash-and-burn, where LAI can reach primary forest levels ( LAI = 4 - 6) in 5 yr. After 12 to 14 yr, the colonizing vegetation returned some components of forest structure to values reported for primary forest. Basal area and LAI were 50% - 60%, canopy cover and stem density were nearly 100%, and the rapid tree-dominated biomass accrual was 25% - 50% of values reported for primary forest. Biomass accumulation may reach an asymptote earlier than expected because of even-aged, monospecific, untiered stand structure. The very slow leaf area accumulation relative to biomass and to reported values for recovery following slash-and-burn indicates a different canopy development pathway that warrants further investigation of causes ( e. g., nutrient limitations, competition) and effects on processes such as evapotranspiration and soil water uptake, which would influence long-term recovery rates and have regional implications

    Factors Influencing Final Outcomes in Patients with Shoulder Pain: A Retrospective Review

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    Study Design Retrospective cohort. Introduction Rehabilitation interventions are commonly prescribed for patients with shoulder pain, but it is unclear what factors may help clinicians\u27 prognosis for final outcomes. Purpose of the Study The purpose of this study is to determine what factors are the best predictors of improved patient-reported outcomes at discharge in patients with shoulder pain. Methods Retrospective chart review of 128 patients presenting with shoulder pain to an outpatient physical therapy clinic. Chart review captured data regarding patient demographics, treatment interventions, patient history, and patient-reported outcome scores. The primary dependent variable was the overall change score of the QuickDASH (initial to discharge). Thirty-eight predictor variables were entered into a forward stepwise multivariate linear regression model to determine which variables and to what degree contributed to the dependent variable. Results The linear regression model identified 5 predictor variables that yielded an R = 0.74 and adjusted R2 = 0.538 (P \u3c .001). The 5 predictor variables identified in order of explained variance are QuickDASH change at the fifth visit, a total number of visits, initial QuickDASH score, scapular retraction exercise, and age. Discussion Early change scores, equal to minimal detectable change scores on patient-reported outcomes appear to be strong indicators that patients with shoulder pain are on a positive trajectory to benefit from rehabilitation. Conclusion Using patient-reported outcomes throughout care, not just at the start and end of care, will provide therapist feedback regarding patient\u27s progress and indicate treatment effectiveness. Levels of Evidence 4

    Specificity of the Minimal Clinically Important Difference of the Quick Disabilities of the Arm Shoulder and Hand (QDASH) for Distal Upper Extremity Conditions

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    Retrospective cohort design. The minimal clinically important difference (MCID) for the quick Disabilities of the Arm, Shoulder and Hand (QDASH) has been established using a pool of multiple conditions, and only exclusively for the shoulder. Understanding diagnoses-specific threshold change values can enhance the clinical decision-making process. Before and after QDASH scores for 406 participants with conditions of surgical distal radius fracture, non-surgical lateral epicondylitis, and surgical carpal tunnel release were obtained. The external anchor administered at each fourth visit was a 15-point global rating of change scale. The test-retest reliability of the QDASH was moderate for all diagnoses: intraclass correlation coefficient model 2, 1, for surgical distal radius = 0.71; non-surgical lateral epicondylitis = 0.69; and surgical carpal tunnel = 0.69. The minimum detectable change at the 90% confidence level was 25.28; 22.49; and 27.63 points respectively; and the MCID values were 25.8; 15.8 and 18.7, respectively. For these three distal upper extremity conditions, a QDASH MCID of 16-26 points could represent the estimate of change in score that is important to the patient and guide clinicians through the decision-making process

    A Retrospective Cohort Study of QuickDASH Scores for Three Hand Therapy Acute Upper Limb Conditions

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    Introduction: The QuickDASH is a valid and reliable outcome measure widely used to assess the function and pain in arm, shoulder, and hand disabilities. A recent study introduced a QuickDASH 80% cut point test to gauge patients at risk of poor outcomes. However, the utility of this test has not been validated. Purpose: To determine typical QuickDASH scores for three upper limb conditions and to test the sensitivity and specificity of the QuickDASH 80% cut point test in predicting patients at risk of poor outcomes. Methods: This is a retrospective study with a total of 406 patient records for whom QuickDASH scores were examined. The sensitivity and specificity of the QuickDASH 80% cut point test was investigated for three acute upper limb conditions seen in hand therapy: surgical distal radius fracture, nonsurgical lateral epicondylitis, and carpal tunnel release. Results: Typical scores were determined for three upper limb conditions. The QuickDASH 80% cut point test per upper limb condition returned poor sensitivity between 28.57% and 41.67%. Conclusion: The results did not support the QuickDASH 80% cut point test as a predictor of final outcome in these three patient populations. Patients with the worse initial 20% scores were not correctly classified as worse 20% final scores. This study provides summary data from three upper limb conditions to provide clinicians with comparison data to establish goals and educate patients

    Descriptive Analysis of Common Functional Limitations Identified by Patients with Shoulder Pain

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    Context: Recent establishment of G-codes by the US government requires therapists to report function limitations at initial evaluation. Limited information exists specific to the most common limitations in patients with shoulder pain. Objective: To describe the most commonly expressed shoulder limitations with activities and their severity/level of impairment from a patient’s perspective on the initial evaluation. Design: Descriptive. Setting: Patients reporting pain with overhead activity and seeking medical attention from one orthopedic surgeon were recruited as part of a cohort study. Patients: 176 with shoulder superior labral tear from anterior to posterior (SLAP), subacromial impingement, combined SLAP and rotator cuff, and nonspecific (female = 53, age = 41 ± 13 y; male = 123, age = 41 ± 12 y). Interventions: Data were obtained on the initial visit from the Patient-Specific Functional Scale (PSFS) questionnaire. Three researchers extracted meaningful concepts from the PSFS and linked them to the International Classification of Functioning (ICF) categories according to established ICF linking rules. Results: 176 participants yielded 765 meaningful concepts that were linked to the ICF with a 66% agreement between researchers before consensus. There were no differences between diagnoses. Of all patients, 88% reported functional limitations coded into meaningful concepts as represented by 10 ICF codes; 634 (83%) meaningful concepts were linked to the activities and participation domain while 129 (17%) were linked to the body function domain. Only 2 reported functional limitations that were considered nondefinable (nd). The overall average initial impairment score on the PSFS = 4 ± 2.5 out of 10 points. Conclusion: Meaningful concepts from the activities and participation domain were most commonly identified as functional limitations and were more prevalent than limitations from the body function domain. This information helps identify some of the most common limitations in patients with shoulder pain that therapists can use to efficiently document patient functional impairment

    Adherence of Individuals in Upper Extremity Rehabilitation: A Qualitative Study

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    OBJECTIVE: To describe the rehabilitation experiences, expectations, and treatment adherence of patients receiving upper extremity (UE) rehabilitation who demonstrated discrepancy between functional gains and overall improvement. DESIGN: Qualitative (phenomenologic) interviews and analysis. SETTING: Outpatient UE rehabilitation. PARTICIPANTS: Patients with acute UE injuries (N=10). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Concerns related to UE rehabilitation patients demonstrating discrepancy between outcome measures. RESULTS: Five key themes emerged from the interviews of patients demonstrating discrepancy in their self-reported patient outcomes: (1) desire to return to normal, (2) initial anticipation of brief recovery, (3) trust of therapist, (4) cannot stop living, and (5) feelings of ambivalence. Challenges included living with the desire to move back into life. Multiple factors affected patient adherence: cost of treatment, patient-provider relation (difference between therapist and patient understanding on what is important for treatment), and patients expecting the treating therapists to be an expert and fix their problem. CONCLUSIONS: Patient adherence to UE rehabilitation presents many challenges. Patients view themselves as laypersons and seek the knowledge of a dedicated therapist who they trust to spend time with them to understand what they value as important and clarify their injury, collaboratively make goals, and explain the intervention to get them in essence, back into life, in the minimal required time. When categorized according to the World Health Organization\u27s multidimensional adherence model, domains identified in this model include social and economic, health care team and system, condition-related, therapy-related, and patient-related dimensions. Assessing factors identified to improve efficiency and effectiveness of clinical management can enhance patient adherence
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