Adjunctive yoga v. health education for persistent major depression: a randomized controlled trial.

BACKGROUND: The objective of this study was to determine whether hatha yoga is an efficacious adjunctive intervention for individuals with continued depressive symptoms despite antidepressant treatment. METHOD: We conducted a randomized controlled trial of weekly yoga classes (n = 63) v. health education classes (Healthy Living Workshop; HLW; n = 59) in individuals with elevated depression symptoms and antidepressant medication use. HLW served as an attention-control group. The intervention period was 10 weeks, with follow-up assessments 3 and 6 months afterwards. The primary outcome was depression symptom severity assessed by blind rater at 10 weeks. Secondary outcomes included depression symptoms over the entire intervention and follow-up periods, social and role functioning, general health perceptions, pain, and physical functioning. RESULTS: At 10 weeks, we did not find a statistically significant difference between groups in depression symptoms (b = -0.82, s.e. = 0.88, p = 0.36). However, over the entire intervention and follow-up period, when controlling for baseline, yoga participants showed lower levels of depression than HLW participants (b = -1.38, s.e. = 0.57, p = 0.02). At 6-month follow-up, 51% of yoga participants demonstrated a response (⩾50% reduction in depression symptoms) compared with 31% of HLW participants (odds ratio = 2.31; p = 0.04). Yoga participants showed significantly better social and role functioning and general health perceptions over time. CONCLUSIONS: Although we did not see a difference in depression symptoms at the end of the intervention period, yoga participants showed fewer depression symptoms over the entire follow-up period. Benefits of yoga may accumulate over time.

The relationships among physical activity, sedentary behaviour, obesity and quitting behaviours within a cohort of smokers in California.

BACKGROUND: Smoking, insufficient physical activity (PA), sedentary behaviour (SB) and obesity are leading risk factors for morbidity and premature mortality. Few studies examining the relationship between these behavioural risk factors and quitting behaviours among cohorts of smokers have been published. PURPOSE: The goals of this study are to examine the cross-sectional relationships among behavioural health risk factors (insufficient PA, SB and obesity) and past year quitting behaviours within a sample of smokers. METHODS: The California Smokers Cohort, conducted from 2011 through 2013, is a population-based survey of adult smokers in California. Using follow-up data (n = 1050), participants' self-reported health behaviours and past year quitting behaviours were examined in univariate analyses and multivariate logistic regression analyses controlling for demographic covariates. RESULTS: In univariate analyses examining health behaviours among smokers, all three health behaviours examined (PA, SB and obesity) were related, and significantly more obese smokers with high PA and low SB reported a ≥20% smoking rate reduction than smokers with other combinations of health behaviours (48.8%, Chi-squared = 4.765, P = 0.045). In multivariate models adjusted for sociodemographic characteristics, obese smokers (odds ratio [OR] = 1.450, 95% confidence interval [CI]: 1.088-1.932, P = 0.011) and smokers with higher levels of PA (OR = 1.448, 95% CI: 1.111-1.887, P = 0.006) were more likely to report a past year ≥24-hour quit attempt regardless of SB, and obese smokers (OR = 1.760, 95% CI: 1.095-2.828, P = 0.019) were more likely to report being quit for ≥30 days regardless of PA and SB. CONCLUSIONS: Overall, the results demonstrated that more physically active and obese smokers were more likely to report positive strides towards quitting. These findings support the potential positive effect of addressing multiple health behaviours along with smoking.

Spatial and temporal genetic structure in a hybrid cordgrass invasion.

Invasive hybrids and their spread dynamics pose unique opportunities to study evolutionary processes. Invasive hybrids of native Spartina foliosa and introduced S. alterniflora have expanded throughout San Francisco Bay intertidal habitats within the past 35 years by deliberate plantation and seeds floating on the tide. Our goals were to assess spatial and temporal scales of genetic structure in Spartina hybrid populations within the context of colonization history. We genotyped adult and seedling Spartina using 17 microsatellite loci and mapped their locations in three populations. All sampled seedlings were hybrids. Bayesian ordination analysis distinguished hybrid populations from parent species, clearly separated the population that originated by plantation from populations that originated naturally by seed and aligned most seedlings within each population. Population genetic structure estimated by analysis of molecular variance was substantial (F(ST)=0.21). Temporal genetic structure among age classes varied highly between populations. At one population, the divergence between adults and 2004 seedlings was low (F(ST)=0.02) whereas at another population this divergence was high (F(ST)=0.26). This latter result was consistent with local recruitment of self-fertilized seed produced by only a few parental plants. We found fine-scale spatial genetic structure at distances less than ∼200 m, further supporting local seed and/or pollen dispersal. We posit a few self-fertile plants dominating local recruitment created substantial spatial genetic structure despite initial long-distance, human dispersal of hybrid Spartina through San Francisco Bay. Fine-scale genetic structure may more strongly develop when local recruits are dominated by the offspring of a few self-fertile plants.

Rapid asymptotic species accumulation in phytophagous insect communities: the pests of cacao.

The number of cacao insect pests is described by a species-area curve. Either annual cacao productivity or area in cultivation of the crop predicts the number of associated insect pest species, when the world's cacao-producing regions are compared. Analysis of covariance does not discriminate different species-area regressions for native as opposed to nonnative cacao-producing regions; the numbers of insect pest species per unit area of cacao in regions of long-standing cultivation do not exceed the numbers in regions of recent introduction. This demonstrates that the number of cacao insect pest species rises rapidly to an asymptote set by the area in cultivation in each region.

Ecology. Biological control of invading species--risk and reform.

Conservation relies increasingly on biological control (BC) of organisms that invade in natural and agricultural areas throughout the world. However, some BC organisms have harmed native species. In the United States, regulations are based on old laws meant to bar agricultural pests, and these are particularly ineffective in protecting native invertebrate animals. Improved ecological safety of BC depends on recognizing that BC is not appropriate for every pest, factoring ecological safety into the selection of BC agents, and limiting the importation and dissemination of agents that can harm either native animals or plants. Reasonable reform of BC will insure the viability of this valuable tool for both agriculture and conservation.

Long-distance dispersal by a parasitoid (Anagrus delicatus, Mymaridae) and its host.

We demonstrate that an egg parasitoid, Anagrus delicatus (Mymaridae, Hymenoptera) and its host, Prokelesia marginata (Delphacidae, Homoptera) regularly disperse 1 km or more in a north Florida saltmarsh. Anagrus delicatus were caught on yellow sticky traps on offshore islets and oyster bars throughout the spring, summer, and fall, whereas P. marginata were caught during one pulse in the spring. Parasitism rates were higher on offshore islets than at mainland sites, even though egg densities were higher at the mainland sites. The majority of parasitoids caught offshore were females. Long-distance dispersal by A. delicatus may be a cause of inverse density-dependent or density-independent spatial patterns of parasitism and may represent a risk-spreading strategy.

High mortality, fluctuation in numbers, and heavy subterranean insect herbivory in bush lupine, Lupinus arboreus.

Sporadic patchy die-off of bush lupine, Lupinus arboreus, has long been known. We describe in detail a series of these incidents on the central California coast, based upon observational and comparative evidence. Stands of thousands of plants die, while nearby mature plants live on. In some sites, repeated die-off followed by regeneration from the seed bank has led to the cover and density of this woody, perennial plant fluctuating widely over the 40 year period for which records exist. Root damage by caterpillars of the ghost moth or "swift" Hepialus californicus (Lepidoptera, Hepialidae) is a major cause of individual bush death and a probable cause of die-off of stands of lupine. Hidden from view underground, a few of these insects readily kill a juvenile or young mature plant by girdling and reaming-out roots. The mass mortality of L. arboreus that we observed involved heavy root damage by these caterpillars in evenaged stands of plants in their first (1.5-year-old) or second (2.5-year-old) flowering season. The injured plants set seed before dying. Older, larger bush lupines better withstood root damage. In plants aged 3 or more years, damage and mortality were correlated with the intensity of ghost moth caterpillars in the roots. At the highest intensity (mean = 37.5, maximum = 62 caterpillars/root), a stand of large, old L. arboreus suffered 41% mortality; 45% of root cambium (median value) was destroyed by feeding caterpillars. Mass death of mature L. arboreus was not correlated with folivory, and leaf damage ranged from nil to moderate in instances of die-off. The western tussock moth, Orgyia vetusta, accounted for the highest levels of folivory, but this insect was rare when die-offs occurred. The lowest lupine mortality rates in our study occurred where tussock caterpillar intensities were high and where plants were repeatedly defoliated by this insect. However, experimental defoliation by high, but realistic, intensities of tussock moth caterpillars resulted in some mortality of mature bushes, and the combined effects of leaf and root herbivory have yet to be assessed. In its natural range on the California coast, bush lupine has several additional species of insect herbivores that can be locally abundant and injurious to the plant, although none is associated with die-off. Subterranean natural enemies of ghost moth caterpillars may play a role in the patchy waxing and waning of this shrub. Locally, a new species of entomophagous nematode (Heterorhabditis sp.) cause high mortality in the soil, before ghost moth caterpillars have entered the root. This natural enemy may thus afford lupines protection from heavy underground herbivory.

Entomopathogenic nematodes: natural enemies of root-feeding caterpillars on bush lupine.

A new species of soil-dwelling entomopathogenic nematode Heterorhabditis hepialus killed up to 100% (mean=72%) of root-boring caterpillars of a ghost moth Hepialus californicus in coastal shrub lands. When unchecked, ghost moth caterpillars killed bush lupine, Lupinus arboreus. Here we describe this strange food chain. Although unappreciated by ecologists, entomopathogenic nematodes are widespread and probably one of the most important groups of natural enemies for underground insects. The free-living infective juvenile (IJ) of entomopathogenic nematodes searches for host insects in the soil. A single IJ can kill a host, although several often invade together. After entering the host through a spiracle or other orifice, the IJ regurgitates its symbiotic bacterium, Photorhabdus luminescens, which kills the host within 48 h. The bacteria digest the cadaver and provide food for the exponentially growing nematode population inside. The bacteria produce antibiotics and other noxious substances that protect the host cadaver from other microbes in the soil. When the cadaver is exhausted of resources, IJs break the host integument and can disperse. As many as 420,000 IJs can be produced within a large ghost moth caterpillar. Surface soil of the lupine rhizosphere is the primary habitat of IJs of H. hepialus. Attracted to waste gases emitted by insects, the 0.5-mm-long IJs can move 6 cm/day through moist soil. Prevalences of H. hepialus ranged from as high as 78% of rhizospheres in some lupine stands to almost zero in others, but it was absent from no stand at our study site. Field intensities ranged from 0.003 IJs/cm3 of soil to 7.5 IJs/cm3, and correlated roughly with prevalences among sites. Few ghost moth caterpillars (mean=6.7) succeeded in entering lupine roots where prevalence of H. hepialus was highest, and this stand had lowest mortality (0.02) of mature bush lupine. In the three stands with lowest prevalence (mean = 2%) of this nematode, many caterpillars (mean = 38.5) entered roots, and lupine mortality was high (range = 0.41-1.0). Old aerial photographs indicate that the stands with highest recent nematode prevalence have had little or no mass die-off of lupine over the past 40 years. The photos depict repeated die-offs of lupine during the past four decades in stands with lowest recent prevalence of the nematode. This pattern leads us to entertain the hypothesis that the nematode affects vegetation dynamics indirectly through a trophic cascade. Dispersal of entomopathogenic nematodes is little understood. We found that air drying of soil extirpates H. hepialus and speculate that this nematode is dispersed during the wet season in moist soil bits on the exterior of fossorial insects and mammals. H. hepialus colonized some previously unoccupied lupine rhizospheres during the wet winter-spring season and, obversely, became extinct from some rhizosperes as soil dried in summer. Root-feeding insects have only recently been recognized as a force in communities, and the regulation of these important herbivores is still largely an ecological terra incognita. All evidence indicates that entomopathogenic nematodes are found throughout terrestril ecosystems, and we propose that trophic chains similar to those described in this report should not be uncommon.

Effects of motivational interviewing on smoking cessation in adolescents with psychiatric disorders.

OBJECTIVE: To test the hypothesis that among adolescent smokers hospitalised for psychiatric and substance use disorders, motivational interviewing (MI) would lead to more and longer quit attempts, reduced smoking, and more abstinence from smoking over a 12 month follow up. DESIGN: Randomised control trial of MI versus brief advice (BA) for smoking cessation, with pre- and post-intervention assessment of self efficacy and intentions to change, and smoking outcome variables assessed at one, three, six, nine, and 12 month follow ups. SETTING: A private, university affiliated psychiatric hospital in Providence, Rhode Island, USA. PATIENTS OR OTHER PARTICIPANTS: Consecutive sample (n = 191) of 13-17 year olds, admitted for psychiatric hospitalisation, who smoked at least one cigarette per week for the past four weeks, had access to a telephone, and did not meet DSM-IV criteria for current psychotic disorder. INTERVENTIONS: MI versus BA. MI consisted of two, 45 minute individual sessions, while BA consisted of 5-10 minutes of advice and information on how to quit smoking. Eligible participants in both conditions were offered an eight week regimen of transdermal nicotine patch upon hospital discharge. MAIN OUTCOME MEASURES: Point prevalence abstinence, quit attempts, changes in smoking rate and longest quit attempt. Proximal outcomes included intent to change smoking behaviour (upon hospital discharge), and self efficacy for smoking cessation. RESULTS: MI did not lead to better smoking outcomes compared to BA. MI was more effective than BA for increasing self efficacy regarding ability to quit smoking. A significant interaction of treatment with baseline intention to quit smoking was also found. MI was more effective than BA for adolescents with little or no intention to change their smoking, but was actually less effective for adolescents with pre-existing intention to cut down or quit smoking. However, the effects on these variables were relatively modest and only moderately related to outcome. Adolescents with comorbid substance use disorders smoked more during follow up while those with anxiety disorders smoked less and were more likely to be abstinent. CONCLUSIONS: The positive effect of MI on self efficacy for quitting and the increase in intention to change in those with initially low levels of intentions suggest the benefits of such an intervention. However, the effects on these variables were relatively modest and only moderately related to outcome. The lack of overall effect of MI on smoking cessation outcomes suggests the need to further enhance and intensify this type of treatment approach for adolescent smokers with psychiatric comorbidity.

A taxometric analysis of MMPI-2 Infrequency scales [F and F(p)] in clinical settings.

The typology of overreporting, which is a deliberate attempt to amplify symptoms, simulate psychopathology, or understate coping capacities, was examined using taxometric procedures with Minnesota Multiphasic Personality Inventory-2 (MMPI-2) Infrequency scales [F and F(p)] in psychiatric inpatient and Veterans Affairs (VA) medical center treatment settings. Overreporting was identified as a taxon using several taxometric procedures, and the multiple estimates of the taxon base rate were consistent within each sample. Mean base-rate estimates were .27 and .19 for the psychiatric inpatient and VA medical center settings, respectively. Overall classification rates ranged from .80 to .97 across the 2 settings, which supports the use of F and F(p) in the identification of overreporting on the MMPI-2 in psychiatric inpatient and VA medical center settings.

Density-vague population change.

Explicit density-dependence differs from density-vagueness in the sort of regulation imposed on populations. Explicit density-dependence implies regulation toward a central equilibrium point, whereas density-vagueness implies population change away from the two extremes of extinction and immense densities. Density-vagueness does not much concern regulation within the broad range of medial densities; it is 'liberal'.

Nonasymptotic species richness models and the insects of british trees.

Nonasymptotic models of species diversity are those that do not consider negative feedback between number of species in a biota and the net rate of species addition. These models propose species richness differences to be primarily the product of geologic age differences among biotas. Nonasymptotic explanations are traditional for various diversity difference spectra, including latitudinal diversity gradients and the greater species richness of ancient compared to young lakes. I review new evidence that renders these nonasymptotic explanations doubtful.The only uncontested evidence in favor of nonasymptotic species accumulation is Southwood's correlation between the number of insect species associated with British tree taxa and the number of Quaternary fossil records of these taxa. I show that nonasymptotic explanations of species richness variation are unacceptable for this system also. The variation in insect species richness among these taxa is well accounted for by a species-area relationship. The species richness asymptote is attained within a few hundred years, and the influence of cumulative host taxon abundance (number of fossil records) upon insect species richness is insignificant after the statistical influence of present-day host plant range is removed. I conclude Southwood's correlation to lack causality; it probably derives from a correlation between the number of fossil records of the host taxa and their present range.

Parasitoid theory: From aggregation to dispersal.

Models that stabilize the Nicholson-Bailey equations of population interactions have dominated theory about insect pests and their natural enemies. However, nonequilibrium behavior is conspicuous in real interactions, and versions of these models that are based on extremely concise descriptions of aggregation of risk to pests are simplistic in ignoring density relationships and movement within generations. Recent theory is less concerned with equilibrium. Within generations, attention to details of enemy movement, foraging and aggregation leads to models that actually predict pest mortality patterns for specific cases. Among generations, dispersal is a key facet of nonequilibrium persistence. Dispersing parasitoids can cause high local mortalities of host insects.

Species richness of the parasitic fungi of british trees.

The species richness of fungi associated with British trees is described by a significant species/area curve (r = 0.53, 0.01 > P > 0.001). Introduced tree species cannot be shown to have fewer fungal species than natives, per unit distributional range about Britain. Also, among natives and among introductions, older host taxa do not have more fungal species than do younger ones. This indicates the species richness of fungi to rapidly reach the limit set by host range, within ecological time. The slope of the species/area relationship for fungi is one-fourth that for insects; we propose that this is due to the inherently greater dispersability of fungi. Finally, the species/area regression residuals for fungi are correlated with those for insects (r = 0.65, 0.001 > P), suggesting plant defense mechanisms may be generally effective to plant parasites, be they insects or fungi.

Origin and genetic diversity of Spartina anglica (Poaceae) using nuclear DNA markers.

Spartina alterniflora, introduced into the UK in the 1800s, was the seed parent in an interspecific hybridization with S. maritima. The sterile F1 hybrid S. ×townsendii gave rise to the fertile allopolyploid S. anglica by chromosomal doubling. Previous chromosome, isozyme, and cpDNA surveys did not reveal notable genetic variation within either the parental or the hybrid species. We used nuclear DNA markers (random amplified polymorphic DNA ([RAPD]) and inter-simple sequence repeats (ISSR) to further explore the origin, diversity, and parentage of S. anglica. We found DNA fragments in S. ×townsendii were the aggregate of diagnostic DNA fragments from S. maritima and S. alterniflora, thus confirming its hybrid origin. The S. ×townsendii genotype was identical to most of the S. anglica individuals analyzed, establishing the genetic concordance of these two taxa. We found widespread genetic variation within S. anglica. This could indicate that S. anglica arose several times, from different S. maritima sires. Alternatively, alleles could have been lost through recombination and/or through loss of entire chromosomes in S. anglica. Finally, all but one S. anglica individual had a S. alterniflora component that was indistinguishable from a S. alterniflora plant extant in Marchwood, UK, leaving open the possibility that this plant is the actual seed parent of S. anglica.