Universally Coupled Massive Gravity

We derive Einstein's equations from a linear theory in flat space-time using free-field gauge invariance and universal coupling. The gravitational potential can be either covariant or contravariant and of almost any density weight. We adapt these results to yield universally coupled massive variants of Einstein's equations, yielding two one-parameter families of distinct theories with spin 2 and spin 0. The Freund-Maheshwari-Schonberg theory is therefore not the unique universally coupled massive generalization of Einstein's theory, although it is privileged in some respects. The theories we derive are a subset of those found by Ogievetsky and Polubarinov by other means. The question of positive energy, which continues to be discussed, might be addressed numerically in spherical symmetry. We briefly comment on the issue of causality with two observable metrics and the need for gauge freedom and address some criticisms by Padmanabhan of field derivations of Einstein-like equations along the way.Comment: Introduction notes resemblance between Einstein's discovery process and later field/spin 2 project; matches journal versio

Ecology and economics of using native managed bees for almond pollination

Native managed bees can improve crop pollination, but a general framework for evaluating the associated economic costs and benefits has not been developed. We conducted a cost–benefit analysis to assess how managing blue orchard bees (Osmia lignaria Say [Hymenoptera: Megachildae]) alongside honey bees (Apis mellifera Linnaeus [Hymenoptera: Apidae]) can affect profits for almond growers in California. Specifically, we studied how adjusting three strategies can influence profits: (1) number of released O. lignaria bees, (2) density of artificial nest boxes, and (3) number of nest cavities (tubes) per box. We developed an ecological model for the effects of pollinator activity on almond yields, validated the model with published data, and then estimated changes in profits for different management strategies. Our model shows that almond yields increase with O. lignaria foraging density, even where honey bees are already in use. Our cost–benefit analysis shows that profit ranged from −US$1,800 to US$2,800/ acre given different combinations of the three strategies. Adding nest boxes had the greatest effect; we predict an increase in profit between low and high nest box density strategies (2.5 and 10 boxes/acre). In fact, the number of released bees and the availability of nest tubes had relatively small effects in the high nest box density strategies. This suggests that growers could improve profits by simply adding more nest boxes with moderate number of tubes in each. Our approach can support grower decisions regarding integrated crop pollination and highlight the importance of a comprehensive ecological economic framework for assessing these decisions

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

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

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

Adherence of Individuals in Upper Extremity Rehabilitation: A Qualitative Study

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

The Schwarzschild black hole as a point particle

The description of a point mass in general relativity (GR) is given in the framework of the field formulation of GR where all the dynamical fields, including the gravitational field, are considered in a fixed background spacetime. With the use of stationary (not static) coordinates non-singular at the horizon, the Schwarzschild solution is presented as a point-like field configuration in a whole background Minkowski space. The requirement of a stable $\eta$-causality stated recently in [J.B.Pitts and W.C.Schieve, Found. Phys., v. 34, 211 (2004)] is used essentially as a criterion for testing configurations.Comment: LATEX, 8 pages, no figure

Faddeev Calculations of Proton-Deuteron Radiative Capture with Exchange Currents

pd capture processes at various energies have been analyzed based on solutions of 3N-Faddeev equations and using modern NN forces. The application of the Siegert theorem is compared to the explicit use of $\pi$- and $\rho$-like exchange currents connected to the AV18 NN interaction. Overall good agreement with cross sections and spin observables has been obtained but leaving room for improvement in some cases. Feasibility studies for 3NF's consistently included in the 3N continuum and the 3N bound state have been performed as well.Comment: Minor changes in notation, ps files for figure

Background-Independence

Intuitively speaking, a classical field theory is background-independent if the structure required to make sense of its equations is itself subject to dynamical evolution, rather than being imposed ab initio. The aim of this paper is to provide an explication of this intuitive notion. Background-independence is not a not formal property of theories: the question whether a theory is background-independent depends upon how the theory is interpreted. Under the approach proposed here, a theory is fully background-independent relative to an interpretation if each physical possibility corresponds to a distinct spacetime geometry; and it falls short of full background-independence to the extent that this condition fails.Comment: Forthcoming in General Relativity and Gravitatio

A Model for the Analysis of Caries Occurrence in Primary Molar Tooth Surfaces

Recently methods of caries quantification in the primary dentition have moved away from summary ‘whole mouth’ measures at the individual level to methods based on generalised linear modelling (GLM) approaches or survival analysis approaches. However, GLM approaches based on logistic transformation fail to take into account the time-dependent process of tooth/surface survival to caries. There may also be practical difficulties associated with casting parametric survival-based approaches in a complex multilevel hierarchy and the selection of an optimal survival distribution, while non-parametric survival methods are not generally suitable for the assessment of supplementary information recorded on study participants. In the current investigation, a hybrid semi-parametric approach comprising elements of survival-based and GLM methodologies suitable for modelling of caries occurrence within fixed time periods is assessed, using an illustrative multilevel data set of caries occurrence in primary molars from a cohort study, with clustering of data assumed to occur at surface and tooth levels. Inferences of parameter significance were found to be consistent with previous parametric survival-based analyses of the same data set, with gender, socio-economic status, fluoridation status, tooth location, surface type and fluoridation status-surface type interaction significantly associated with caries occurrence. The appropriateness of the hierarchical structure facilitated by the hybrid approach was also confirmed. Hence the hybrid approach is proposed as a more appropriate alternative to primary caries modelling than non-parametric survival methods or other GLM-based models, and as a practical alternative to more rigorous survival-based methods unlikely to be fully accessible to most researchers