The Evolution of Feeding Mechanics in the Danioninae, or Why Giant Danios Don't Suck Like Zebrafish

By linking anatomical structure to mechanical performance we can improve our understanding of how selection shapes morphology. Here we examined the functional morphology of feeding in fishes of the subfamily Danioninae (order Cypriniformes) to determine aspects of cranial evolution connected with their trophic diversification. The Danioninae comprise three major lineages and each employs a different feeding strategy. We gathered data on skull form and function from species in each clade, then assessed their evolutionary dynamics using phylogenetic-comparative methods. Differences between clades are strongly associated with differences in jaw protrusion. The paedomorphic Danionella clade does not use jaw protrusion at all, members of the Danio clade use jaw protrusion for suction production and prey capture, and members of the sister clade to Danio (e.g., Devario and Microdevario) use jaw protrusion to retain prey after capture. The shape of the premaxillary bone is a major determinant of protrusion ability, and premaxilla morphology in each of these lineages is consistent with their protrusion strategies. Premaxilla shapes have evolved rapidly, which indicates that they have been subjected to strong selection. We compared premaxilla development in giant danio (Devario aequipinnatus) and zebrafish (Danio rerio) and discuss a developmental mechanism that could shift danionine fishes between the feeding strategies employed by these species and their respective clades. We also identified a highly integrated evolutionary module that has been an important factor in the evolution of trophic mechanics within the Danioninae.

Auditory-motor coupling of bilateral finger tapping in children with and without DCD compared to adults

The ability to modulate bilateral finger tapping in time to different frequencies of an auditory beat was studied. Twenty children, 7 years of age, 10 with and 10 without developmental coordination disorder (DCD), and 10 adults tapped their left index and right middle fingers in an alternating pattern in time with an auditory signal for 15s (four trials each, randomly, at 0.8, 1.6, 2.4, 3.2 Hz per finger). Dominant and non-dominant finger data were collapsed since no differences emerged. All three groups were able to modulate their finger frequency across trials to closely approximate the signal frequency but children with DCD were unable to slow down to the lowest frequency. Children with DCD were more variable in tap accuracy (SD of relative phase) and between finger coordination than typically developing children who were respectively more variable than the adults. Children with DCD were unable to consistently synchronize their finger with the beat. Adults were tightly synchronized and often ahead of the beat while children without DCD tended to be behind the beat. Overall, these results indicated that children with DCD can only broadly match their finger movements to an auditory signal with variability and poor synchronicity as key features of their auditory-fine-motor control. Individual inspection of the data revealed that five children with DCD had difficulty matching the slowest frequencies and that these children also had higher variability and lower percentile MABC scores from the movement assessment battery for children (MABC) than other children with DCD. Three children with DCD were more variable only at higher frequencies and two performed like typically developing children.

Perception-action coupling in children with and without DCD: Frequency locking between task-relevant auditory signals and motor responses in a dual-motor task

BACKGROUND

The current research examines the relationship between perceptual and motor processes, known as perception-action or sensorimotor coupling, and the potential differences in perception-action coupling among children with and without Developmental Coordination Disorder (DCD) and adults in a gross-motor co-ordination task (clapping while marching) when a task-relevant driving sensory signal is present.

METHODS

Ten children with DCD (7.32 + 0.23 years), eight typically developing (TD) children who were age-, gender- and racially/ethnically matched (6.91 + 0.24 years) and 10 college-aged adults were participants in this study. Participants clapped and marched to an auditory beat at four different frequencies: 0.8, 1.2,1.6 and 2.0 Hz. The relative timing measures of mean relative phase (MRP) and variability of relative phase (VRP) were calculated and compared using 3 (group) x 4 (frequency) x 2 (limb) anovas. Qualitatively, participants were assessed for the presence of absolute coupling (100% + 15% MRP).

RESULTS

Statistically significant differences in MRP occurred for coupling, frequency and group, and post hoc analysis indicated that the adult group differed from both the DCD and TD groups, who did not differ from each other. In VRP, there were significant main effects for coupling and group, and a significant interaction between group and frequency, with post hoc analysis indicating the DCD group to be different from the TD and adult groups. Qualitatively, both the adult and TD groups increased in the number of participants who adopt absolute coupling as frequency increases. In contrast, the DCD participants adopt this absolute coupling far less frequently overall; in fact, the number of participants adopting this pattern decreases as frequency increases.

CONCLUSIONS

These results indicate that children with DCD have difficulties with both the co-ordination and the control of their perception-action coupling for this particular task.

Adoption of the AHCPR Clinical Practice Guideline for Smoking Cessation: a survey of California's HMOs

OBJECTIVE

Our objective was to assess the degree to which health maintenance organizations (HMOs) and Medicaid managed care (MMC) plans in California have adopted the 1996 AHCPR Clinical Practice Guideline for Smoking Cessation. (AHCPR [U.S. Agency for Health Care Policy and Research] was renamed AHRQ [Agency for Healthcare Research and Quality] in 1999.)

METHODS

A fax survey of 13 licensed HMOs and 21 MMC plans operating in California in 1999 with up to 10 follow-up contacts by telephone, mail, fax, and/or electronic mail.

RESULTS

Awareness of the AHCPR guideline is widespread, and all HMOs in California in 1999 offered coverage for at least one treatment for smoking cessation. We found that 77% of the HMOs in California were aware of the AHCPR guideline, but less than half had used it to design benefits or distribute treatment guidelines to medical care providers in their networks. While only 23% of California HMOs covered the nicotine patch or gum, 69% covered at least one form of the pharmacotherapy and one type of counseling to treat tobacco dependence. In addition, a majority of the HMOs and MMC plans inform their members about coverage for smoking cessation treatments and inform providers about their role in helping smokers to quit.

CONCLUSION

Considerable progress has been made in increasing access to effective smoking cessation treatments in California's managed care organizations over the last 10 years. Future efforts and research must concentrate on: (1) adopting the 2000 Public Health Service Clinical Practice Guideline on Treating Tobacco Use and Dependence, (2) increasing purchaser demand for coverage of tobacco dependence treatments, (3) increasing health plan documentation and monitoring of member smoking status, and (4) increasing provider provision of effective tobacco dependence treatments.

Variations in treatment benefits influence smoking cessation: results of a randomised controlled trial

OBJECTIVE

To assess the impact and costs of coverage for tobacco dependence treatment benefits with no patient cost sharing for smokers with employer sponsored coverage in two large independent practice association (IPA) model health maintenance organisations (HMOs) in California, USA.

METHODS

A randomised experimental design was used. 1204 eligible smokers were randomly assigned either to the control group, which received a self-help kit (video and pamphlet), or to the treatment group, which received the self-help kit and fully covered benefits for over the counter (OTC) nicotine replacement therapy (NRT) gum and patch, and participation in a group behavioural cessation programme with no patient cost sharing.

RESULTS

The quit rates after one year of follow up were 18% in the treatment group and 13% in the control group (adjusted odd ratio (OR) 1.6, 95% confidence interval (CI) 1.1 to 2.4), controlling for health plan, sociodemographics, baseline smoking characteristics, and use of bupropion. Rates of quit attempts (adjusted OR 1.4, 95% CI 1.1 to 1.8) and use of nicotine gum or patch (adjusted OR 2.3, 95% CI 1.6 to 3.2) were also higher in the treatment group. The annual cost of the benefit per user who quit ranged from $1495 to $965 or from $0.73 to $0.47 per HMO member per month.

CONCLUSIONS

Full coverage of a tobacco dependence treatment benefit implemented in two IPA model HMOs in California has been shown to be an effective and relatively low cost strategy for significantly increasing quit rates, quit attempts, and use of nicotine gum and patch in adult smokers.

Differences in the kinds of problems consumers report in staff/group health maintenance organizations, independent practice association/network health maintenance organizations, and preferred provider organizations in California

BACKGROUND

Little is known about the extent to which consumers have specific problems with their managed care organizations (MCOs) or whether these problems differ by type of MCO.

OBJECTIVE

To estimate the prevalence at which consumers in managed care report specific problems and to assess whether rates in preferred provider organizations (PPOs), independent practice association (IPA)/network health maintenance organizations (HMOs), and staff/group HMOs differ.

DESIGN

Random probability sample of insured adults weighted to reflect the underlying population in California. A computer-assisted telephone interview survey was conducted in September 1997. Logistic regression models estimate the adjusted odds of reporting each problem in the last year in IPA/network HMOs versus PPOs, IPA/network HMOs versus staff/group HMOs, and staff/group HMOs versus PPOs.

SUBJECTS

One thousand two hundred one insured adults who had resided in California for > or = 12 months.

MEASURES

Prevalence of 11 consumer problems in MCOs.

RESULTS

Forty-two percent of adult Californians in managed care in our sample reported > or = 1 problem with their MCO in the last year. Adjusted odds that adults in IPA/ network or staff/group HMOs reported delays in getting needed care, not receiving the most appropriate or needed care, and being forced to change doctors were higher than for adults in PPOs. Adjusted odds that adults in IPA/network HMOs reported difficulty getting a referral to a specialist and difficulty selecting a doctor or hospital were higher than for adults in PPOs and staff/group HMOs. Adjusted odds that adults in staff/ group HMOs reported misunderstandings over benefits and coverage; important benefits not covered; and problems with claims, billing, or payments were lower than for adults in PPOs and IPA/network HMOs. Adjusted odds that consumers in HMOs in our sample reported any problem with their health plan was higher for those in IPA/network HMOs compared with staff/group HMOs. No differences were seen by MCO type in the rates at which consumers reported being denied care or treatment, forced to change medications, or language and communication barriers.

CONCLUSIONS

Rates at which consumers report problems with managed care and the kinds of problems they report differ significantly across different types of MCOs. These findings have important implications for federal and state policy for consumer protections in managed care.