Workers\u27 Compensation and Disability Benefits: The Effect of the Permanent Partial Disability Multiplier and Settlement Method on Back Injury Claims in the State of Tennessee

Back pain is the leading cause of work place disability in Tennessee. The National Council on Compensation Insurance (NCCI, 2002) found that in the United States back claims account for thirty-two (32%) percent of all workers\u27 compensation claims and the average cost of a back claim is roughly fifty (50%) percent higher than the cost of other work-related injuries. Previous research on Tennessee workers\u27 compensation suggests that permanent partial disability benefits (PPD) are a major source of cost and litigation in a court based system (Gardner, Telles, & Moss, 1996; Boden, 1997; Ballantyne, 2003). The workers\u27 compensation system in Tennessee is a court based system. Trial courts have full discretion in determining the amount of permanent partial disability (PPD) awards. Workers\u27 compensation claims may be settled under the following methods: (1) trial; (2) settlement approved by court - complaint filed; (3) settlement approved by court - complaint not filed; and (4) settlement approved by the Tennessee Department of Labor & Workforce Development. Permanent partial disability (PPD) awards for back injuries are dependent upon whether the employer returned the employee to work after injury.1 Permanent partial disability (PPD) indemnity benefit costs in Tennessee can be greatly influenced by the magnitude of the permanent partial disability multiplier (PPDM) (Garnder, Telles, & Moss, 1996; Boden, 1997; Ballantyne, 2003). The use of multipliers to assign permanent partial disability (PPD) indemnity benefits is unique and utilized only by Tennessee (Gardner, Telles, & Moss, 1996; Boden, 1997; Ballantyne, 2003). A previous published study on Tennessee reported that permanent partial disability (PPD) awards for low back injuries vary among judicial districts and that the application of the multipliers may be one of the causes of variation in awards (Boden, 1997). Previous research has not investigated whether permanent partial disability (PPD) awards for back injuries vary by the method of settlement. This study investigated the Tennessee workers\u27 compensation system to determine if benefit variation existed among settlement methods for back injury claims. Workers\u27 compensation claim data from 2000-2003 was obtained from the Tennessee Department of Labor & Workforce Development. Regression analysis was used to determine whether there was a significant difference between group means using a p value of .05. The settlement method found to have the greatest influence on permanent partial disability (PPD) awards in return-to-work and a non-return-to-work claim was trial. A claim resolved at trial was found to be four percent (3.729%) more in permanent partial disability (PPD) indemnity benefits paid when compared to settlements approved by the Tennessee Department of Labor in return-to-work claims and eleven percent (11.406%) more in non-return-to-work claims. Employees with a work-related back injury claim had a forty-three percent (43.5%) probability of having surgery. Of the employees who had back surgery, sixty-one percent (61.3%) were able to return-to-work with their pre-injury employer

Selection strategies to introgress water deficit tolerance derived from Solanum galapagense accession LA1141 into cultivated tomato

Crop wild relatives have been used as a source of genetic diversity for over one hundred years. The wild tomato relative Solanum galapagense accession LA1141 demonstrates the ability to tolerate deficit irrigation, making it a potential resource for crop improvement. Accessing traits from LA1141 through introgression may improve the response of cultivated tomatoes grown in water-limited environments. Canopy temperature is a proxy for physiological traits which are challenging to measure efficiently and may be related to water deficit tolerance. We optimized phenotypic evaluation based on variance partitioning and further show that objective phenotyping methods coupled with genomic prediction lead to gain under selection for water deficit tolerance. The objectives of this work were to improve phenotyping workflows for measuring canopy temperature, mapping quantitative trait loci (QTLs) from LA1141 that contribute to water deficit tolerance and comparing selection strategies. The phenotypic variance attributed to genetic causes for canopy temperature was higher when estimated from thermal images relative to estimates based on an infrared thermometer. Composite interval mapping using BC2S3 families, genotyped with single nucleotide polymorphisms, suggested that accession LA1141 contributed alleles that lower canopy temperature and increase plant turgor under water deficit. QTLs for lower canopy temperature were mapped to chromosomes 1 and 6 and explained between 6.6 and 9.5% of the total phenotypic variance. QTLs for higher leaf turgor were detected on chromosomes 5 and 7 and explained between 6.8 and 9.1% of the variance. We advanced tolerant BC2S3 families to the BC2S5 generation using selection indices based on phenotypic values and genomic estimated breeding values (GEBVs). Phenotypic, genomic, and combined selection strategies demonstrated gain under selection and improved performance compared to randomly advanced BC2S5 progenies. Leaf turgor, canopy temperature, stomatal conductance, and vapor pressure deficit (VPD) were evaluated and compared in BC2S5 progenies grown under deficit irrigation. Progenies co-selected for phenotypic values and GEBVs wilted less, had significantly lower canopy temperature, higher stomatal conductance, and lower VPD than randomly advanced lines. The fruit size of water deficit tolerant selections was small compared to the recurrent parent. However, lines with acceptable yield, canopy width, and quality parameters were recovered. These results suggest that we can create selection indices to improve water deficit tolerance in a recurrent parent background, and additional crossing and evaluation are warranted

Chromatic Properties of Neurons in Macaque Area V2

We recorded from single cells in area V2 of cynomolgus monkeys using standard acute recording techniques. After measuring each cell's spatial and temporal properties, we performed several tests of its chromatic properties using sinewave gratings modulated around a mean gray background. Most cells behaved like neurons in area V1 and their response was adequately described by a model that assumes a linear combination of cone signals. Unlike in V1, we found a subpopulation of cells whose activity was increased or inhibited by stimuli within a narrow range of color combinations. No particular color directions were preferentially represented. V2 cells showing color-specificity, including cells showing narrow chromatic tuning, could be found in any of the stripe compartments, as defined by cytochrome-oxidase (CO) staining. An addition of chromatic contrast facilitated the responses of most neurons to gratings with various luminance contrasts. Neurons in all three CO-compartments gave a significant population response to isoluminant gratings. Receptive fields properties of cells were generally similar for luminance and chromatically defined stimuli. We found only a small number of cells with a clearly identifiable double-opponent receptive field organization. The similarity between the chromatic tuning characteristics of individual color-specific cells in area V2 and psychophysically observed higher order color mechanisms suggests an important role for area V2 in the cortical hierarchy for the processing of color signals

Chromatic properties of neurons in macaque area V2.

We recorded from single cells in area V2 of cynomolgus monkeys using standard acute recording techniques. After measuring each cell's spatial and temporal properties, we performed several tests of its chromatic properties using sine-wave gratings modulated around a mean gray background. Most cells behaved like neurons in area V1 and their responses were adequately described by a model that assumes a linear combination of cone signals. Unlike in V1, we found a subpopulation of cells whose activity was increased or inhibited by stimuli within a narrow range of color combinations. No particular color directions were preferentially represented. V2 cells showing color specificity, including cells showing narrow chromatic tuning, were present in any of the stripe compartments, as defined by cytochrome-oxidase (CO) staining. An addition of chromatic contrast facilitated the responses of most neurons to gratings with various luminance contrasts. Neurons in all three CO compartments gave significant responses to isoluminant gratings. Receptive-field properties of cells were generally similar for luminance and chromatically defined stimuli. We found only a small number of cells with a clearly identifiable double-opponent receptive-field organization

A comparison of neuronal properties in macaque areas V2 and V3

Purpose. To quantitatively assess the spatio-temporal and chromatic properties of cells in area V3 and to compare the processing in this area to that in V2, its preceding stage in the visual pathways. Methods, We recorded extracellularly from single cells in visual areas V2 and V3 of anesthetized and paralyzed macaque monkeys using standard acute recording techniques. The range of receptive field eccentricities was matched in both samples. For each cell, we determined tuning to drifting sinewave gratings of different spatial and temporal frequencies, orientations, directions, sizes and color. Results. Neurons in area V3 preferred lower spatial, but higher temporal frequencies than neurons in area V2. In both V2 and V3, most neurons (>90%) were selective to orientation. Selectivity to size (20%) was also equally frequent in both areas. The largest difference in tuning characteristics was a higher selectivity to direction of motion in V3 (50%) than in V2 (20%). Although overall selectivity for color was about equal in both areas (50%), the tuning characteristics of the color selective cells were quite different. In V2 a significant subpopulation of cells (30%) showed specific responses to a narrow range of colors. In V3 the responses of all cells were well described by a linear summation of cone inputs. Whereas preferred colors were evenly distributed around the color circle in area V2, there was a tendency for V3 cells to prefer yellow-blue modulations. Conclusions. The preference of V3 cells for higher temporal frequencies and the similarity in color tuning to V1, indicate that V3 may not be receiving its main input from V2, as a hierarchical model would predict, but from area V1 directly

Processing of color, form, and motion in macaque area V2

We investigated the representation of color in cortical area V2 of macaque monkeys, and the association of color with other stimulus attributes. We measured the selectivity of individual V2 neurons for color, motion, and form. Most neurons in V2 were orientation selective, about half of them were selective for color, and a minority of cells (about 20) were selective for size or direction. We correlated these physiological measurements with the anatomical location of the cells with respect to the cytochrome oxidase (CO) compartments of area V2. There was a tendency for color-selective cells to be found more frequently in the thin stripes, but color-selective cells also occurred frequently in thick stripes and inter-stripes. We found no difference in the degree of color selectivity between the different CO compartments. Furthermore, there was no negative correlation between color selectivity and selectivity for other stimulus attributes. We found many cells capable of encoding information along more than one stimulus dimension, regardless of their location with respect to the CO compartments. We suggest that area V2 plays an important role in integrating information about color, motion, and form. By this integration of stimulus attributes a cue invariant representation of the visual world might be achieved