8,046 research outputs found
A Differential Overview of Self-Directed Low Back Exercise Programs
Patients with low back pain represent a large percentage of the population frequenting today\u27s clinics. Despite the high prevalence of low back pain in today\u27s clinical setting, it is considered one of the most difficult diagnoses to treat. While practitioners in the field of physical therapy employ a diversity of evaluation and treatment techniques, they all share one common denominator, the goal of limiting pain while improving function and quality of life. Many therapists subscribe to a treatment approach which involves the patient in active individualized self-treatment exercises. Controversy exists as to which treatment approach is most effective and whether an individual or eclectic approach to low back pain is most advantageous.
The purpose of this study is to provide a differential overview of the principles, techniques and approach of three low back exercise programs most often used in today\u27s clinical setting. These include Dynamic Muscular Lumbar Stabilization, the McKenzie Method and Williams Exercises. Through a comprehensive review of the literature, a discussion of the intervetebral disk and lumbopelvic anatomy is presented followed by an in depth description of the clinical usefulness and rationale of each treatment approach. A conclusion as to the significant role that each respective program plays in today\u27s clinical environment is also made
The natural capital framework for sustainable, efficient and equitable decision making
The concept of ‘natural capital’ is gaining traction internationally as recognition grows of the central role of the natural environment in sustaining economic and social well-being. It is therefore encouraging to see the first signs of a ‘natural capital approach’ to decision making being accepted within government policy processes and the private sector. However, there are multiple different understandings of this ‘approach’, many of which misuse or omit key features of its foundations in natural science and economics. To address this, we present a framework for natural capital analysis and decision making that links ecological and economic perspectives
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Brainstem atrophy in focal epilepsy destabilizes brainstem-brain interactions: Preliminary findings.
BACKGROUND: MR Imaging has shown atrophy in brainstem regions that were linked to autonomic dysfunction in epilepsy patients. The brainstem projects to and modulates the activation state of several wide-spread cortical/subcortical regions. The goal was to investigate 1. Impact of brainstem atrophy on gray matter connectivity of cortical/subcortical structures and autonomic control. 2. Impact on the modulation of cortical/subcortical functional connectivity.
METHODS: 11 controls and 18 patients with non-lesional focal epilepsy (FE) underwent heart rate variability (HRV) measurements and a 3 T MRI (T1 in all subjects, task-free fMRI in 7 controls/ 12 FE). The brainstem was extracted, and atrophy assessed using deformation-based-morphometry. The age-corrected z-scores of the mean Jacobian determinants were extracted from 71 5x5x5 mm grids placed in brainstem regions associated with autonomic function. Cortical and non-brainstem subcortical gray matter atrophy was assessed with voxel-based-morphometry and mean age corrected z-scores of the modulated gray matter volumes extracted from 380 cortical/subcortical rois. The profile similarity index was used to characterize the impact of brainstem atrophy on gray matter connectivity. The fMRI was preprocessed in SPM12/Conn17 and the BOLD signal extracted from 398 ROIs (16 brainstem). A dynamic task-free analysis approach was used to identify activation states. Connectivity HRV relationship were assessed with Spearman rank correlations.
RESULTS: HRV was negatively correlated with reduced brainstem right hippocampus/parahippocampus gray matter connectivity in controls (p \u3c .05, FDR) and reduced brainstem to right parietal cortex, lingual gyrus, left hippocampus/amygdala, parahippocampus, temporal pole, and bilateral anterior thalamus connectivity in FE (p \u3c .05, FDR). Dynamic task-free fMRI analysis identified 22 states. The strength of the functional brainstem/cortical connectivity of state 15 was negatively associated with HRV (r = -0.5, p = .03) and positively with decreased brainstem-cortical (0.49, p = .03) gray matter connectivity.
CONCLUSION: The findings of this small pilot study suggest that impaired brainstem-cortex gray matter connectivity in FE negatively affects the brainstem\u27s ability to control cortical activation
Measuring the Intellectual Development of College Students: Testing a Theoretical Framework
The purpose of this research was to test the ability of Perry's scheme of intellectual development to measure the intellectual development of college students. Perry's scheme postulates four broad levels of intellectual development in the college years - dualism, multiplicity, relativity and commitment. A questionnaire was developedfrom items used in the research literature to describe thefour levels and was administered to second and fourth semester college students. Ten college instructors also participated. To test the construct validity of Perry's scheme, different items representing a stage were examined for convergence, while the sets of items representing different stages were examined for divergence. The empirical validity of Perry's scheme was tested by examining student responses in relation to student time in college, cumulative average and gender. The results suggest that rather than stages of development, there are two possible levels or general positions that students take toward knowledge. The first is that knowledge consists of facts and data, and that professors should supply them. The second is that knowledge is a quest in which students have responsibility for their own learning, and are expected to be able to judge the validity of arguments and to identify and defend their own point of view. More successful students had a greater tendency to adopt the second position, but the majority of the students were in agreement with statements describing the second position.L'objet du présent projet était de vérifier la capacité du modèle de développement intellectuel de Perry à mesurer le développement intellectuel des étudiants de niveau collégial. Le modèle de Perry pose comme principe qu'il existe quatre grands niveaux de développement intellectuel durant les années de collège: le dualisme, la multiplicité, la relativité et /'engagement. Nous avons donc élaboré un questionnaire à partir des rubriques couramment employées dans la littérature pour décrire les quatre niveaux, et l'avons administré à des étudiants de collège au deuxième et au quatrième semestres. Dix professeurs de collège y ont également participé. Pour vérifier la validité structurelle du modèle de Perry, nous avons analysé différentes rubriques représentant un stade pour déterminer leur convergence, alors que nous avons cherché à analyser la divergence d'ensembles de rubriques représentant différents stades. Nous avons vérifié la validité empi-rique du modèle de Perry en examinant les réponses des étudiants par rapport au temps passé par l'étudiant au collège, à sa moyenne cumulative et à son sexe. Il ressort de nos résultats qu'au lieu de stades de développement, il y a plutôt deux niveaux ou positions générales possibles que les étudiants adoptent face au savoir. La première est que le savoir se compose de faits et de données, et que les professeurs sont là pour les inculquer aux étudiants. La seconde est que le savoir est une quête dont la responsabilité incombe à chaque étudiant, ceux-ci étant normalement capables de juger de la validité des arguments et de dégager et de défendre leur propre point de vue. On a pu constater que les étudiants les plus brillants optaient généralement pour la deuxième position, alors que la majorité des étudiants étaient d'accord avec les énoncés décrivant cette deuxième position
Nonlinear Integral-Equation Formulation of Orthogonal Polynomials
The nonlinear integral equation P(x)=\int_alpha^beta dy w(y) P(y) P(x+y) is
investigated. It is shown that for a given function w(x) the equation admits an
infinite set of polynomial solutions P(x). For polynomial solutions, this
nonlinear integral equation reduces to a finite set of coupled linear algebraic
equations for the coefficients of the polynomials. Interestingly, the set of
polynomial solutions is orthogonal with respect to the measure x w(x). The
nonlinear integral equation can be used to specify all orthogonal polynomials
in a simple and compact way. This integral equation provides a natural vehicle
for extending the theory of orthogonal polynomials into the complex domain.
Generalizations of the integral equation are discussed.Comment: 7 pages, result generalized to include integration in the complex
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Fuels treatment and wildfire effects on runoff from Sierra Nevada mixed-conifer forests
We applied an eco-hydrologic model (Regional Hydro-Ecologic Simulation System [RHESSys]), constrained with spatially distributed field measurements, to assess the impacts of forest-fuel treatments and wildfire on hydrologic fluxes in two Sierra Nevada firesheds. Strategically placed fuels treatments were implemented during 2011–2012 in the upper American River in the central Sierra Nevada (43 km2) and in the upper Fresno River in the southern Sierra Nevada (24 km2). This study used the measured vegetation changes from mechanical treatments and modelled vegetation change from wildfire to determine impacts on the water balance. The well-constrained headwater model was transferred to larger catchments based on geologic and hydrologic similarities. Fuels treatments covered 18% of the American and 29% of the Lewis catchment. Averaged over the entire catchment, treatments in the wetter central Sierra Nevada resulted in a relatively light vegetation decrease (8%), leading to a 12% runoff increase, averaged over wet and dry years. Wildfire with and without forest treatments reduced vegetation by 38% and 50% and increased runoff by 55% and 67%, respectively. Treatments in the drier southern Sierra Nevada also reduced the spatially averaged vegetation by 8%, but the runoff response was limited to an increase of less than 3% compared with no treatment. Wildfire following treatments reduced vegetation by 40%, increasing runoff by 13%. Changes to catchment-scale water-balance simulations were more sensitive to canopy cover than to leaf area index, indicating that the pattern as well as amount of vegetation treatment is important to hydrologic response
Relativistic and Radiative Corrections to the Mollow Spectrum
The incoherent, inelastic part of the resonance fluorescence spectrum of a
laser-driven atom is known as the Mollow spectrum [B. R. Mollow, Phys. Rev.
188, 1969 (1969)]. Starting from this level of description, we discuss
theoretical foundations of high-precision spectroscopy using the resonance
fluorescence light of strongly laser-driven atoms. Specifically, we evaluate
the leading relativistic and radiative corrections to the Mollow spectrum, up
to the relative orders of (Z alpha)^2 and alpha(Z alpha)^2, respectively, and
Bloch-Siegert shifts as well as stimulated radiative corrections involving
off-resonant virtual states. Complete results are provided for the hydrogen
1S-2P_{1/2} and 1S-2P_{3/2} transitions; these include all relevant correction
terms up to the specified order of approximation and could directly be compared
to experimental data. As an application, the outcome of such experiments would
allow for a sensitive test of the validity of the dressed-state basis as the
natural description of the combined atom-laser system.Comment: 20 pages, 1 figure; RevTe
Preference uncertainty as an explanation of anomalies in contingent valuation: coastal management in the UK
This is the final version. Available on open access from Springer via the DOI in this recordDirectly asking respondents in contingent valuation surveys their willingness-to-pay is one of the few quantitative methods available to assess full economic value (including both use and non-use values) of non-market environmental goods. It therefore remains vitally important to better understand the reasons for consistently observed violations of procedural invariance in such surveys. This paper describes an empirical experiment designed to examine whether uncertainty might provide an explanation for three commonly-observed violations of procedural invariance in contingent valuation. In each case we present a plausible explanation for each anomaly through decision heuristics brought about by respondents trying to answer the question truthfully when their underlying preferences are stable but uncertain. Using a novel semi-parametric estimator we find little evidence to support the idea that anomalies can be resolved through an uncertainty explanation but our experiment provides noteworthy insights into the ways uncertain preferences may be shaped by the nature of contingent valuation questions
Calculation of some determinants using the s-shifted factorial
Several determinants with gamma functions as elements are evaluated. This
kind of determinants are encountered in the computation of the probability
density of the determinant of random matrices. The s-shifted factorial is
defined as a generalization for non-negative integers of the power function,
the rising factorial (or Pochammer's symbol) and the falling factorial. It is a
special case of polynomial sequence of the binomial type studied in
combinatorics theory. In terms of the gamma function, an extension is defined
for negative integers and even complex values. Properties, mainly composition
laws and binomial formulae, are given. They are used to evaluate families of
generalized Vandermonde determinants with s-shifted factorials as elements,
instead of power functions.Comment: 25 pages; added section 5 for some examples of application
Laplace transform of spherical Bessel functions
We provide a simple analytic formula in terms of elementary functions for the
Laplace transform j_{l}(p) of the spherical Bessel function than that appearing
in the literature, and we show that any such integral transform is a polynomial
of order l in the variable p with constant coefficients for the first l-1
powers, and with an inverse tangent function of argument 1/p as the coefficient
of the power l. We apply this formula for the Laplace transform of the memory
function related to the Langevin equation in a one-dimensional Debye model.Comment: 5 pages LATEX, no figures. Accepted 2002, Physica Script
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