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Little Investigation (little + investigation)
Selected AbstractsHarem size and oviposition behaviour in a polygynous bark beetleECOLOGICAL ENTOMOLOGY, Issue 5 2009TANYA M. LATTY Abstract. 1. Harem polygyny can have fitness benefits and costs on females. In bark beetles of the genus Ips the latter may include within-harem competition between larvae. However, earlier competition between females for male care and mating opportunities may also influence oviposition behaviour. There has been relatively little investigation into the relationship between harem size and initial egg output. The present study investigated this relationship in the bark beetle Ips grandicollis. 2. The measure of egg output used was the number of eggs in the gallery with the most eggs in each harem. Mean (±SE) harem size of 242 observed harems was 3.25 ± 0.10. A curvilinear relationship was found between egg output and harem size, with females in smaller harems (one to four females) laying more eggs with increased harem size. However, females in larger harems (five to seven females) laid fewer eggs as harem size increased. The optimal harem size (in terms of number of eggs laid) was close to four females. 3. We found no evidence from a behavioural assay that females could preferentially choose unmated males over mated males with harems of two females. Additionally, the distribution of harem sizes suggests that females distribute themselves among males randomly. 4. The results suggest that harem size has effects on female reproduction that extend beyond larval competition and influence patterns of oviposition. The mechanism that determines why egg laying is greatest at intermediate levels is unknown. There is no evidence that smaller harems belong to lower quality males, but females may adjust egg-laying behaviour in large harems as a result of reduced male attendance or anticipated larval competition. [source] Evidence of concealment behavior by adult rainbow trout and brook trout in winterECOLOGY OF FRESHWATER FISH, Issue 3 2000K. A. Meyer Abstract , There has been little investigation of the winter ecology of adult trout during winter, especially in regard to concealment behavior. We compared day vs night underwater counts of adult rainbow trout and brook trout from four streams. At water temperatures between 1°C and 9°C, daytime counts accounted for 44% and 16% of nighttime snorkeling counts for rainbow trout and brook trout adults, respectively. As winter progressed, nighttime counts declined more so for brook trout than rainbow trout, but the decline was not significant for either species. Nocturnalism of both species was higher in streams with colder water temperatures. We observed few fish within concealment structure; however, by electrofishing concealment habitat during the day, we captured 10 times more adult trout than we counted immediately beforehand by snorkeling. Adult trout were concealed in cobble-boulder substrate and woody debris during the day., [source] Adolescent smoking and depression: evidence for self-medication and peer smoking mediationADDICTION, Issue 10 2009Janet Audrain-McGovern ABSTRACT Aims The nature of the relationship between adolescent smoking and depression is unclear and the mechanisms that account for the comorbidity have received little investigation. The present study sought to clarify the temporal precedence for smoking and depression and to determine whether these variables are linked indirectly through peer smoking. Participants The sample was composed of 1093 adolescents participating in a longitudinal study of the behavioral predictors of smoking adoption. Design and measurements In this prospective cohort study, smoking, depression, peer smoking and other covariates were measured annually from mid-adolescence (9th grade; age 14) to late adolescence (12th grade, age 18). Findings Parallel processes latent growth curve models supported a bidirectional relationship between adolescent smoking and depression, where higher depression symptoms in mid-adolescence (age 14) predicted adolescent smoking progression from mid- to late adolescence (ages 14,18). A significant indirect effect indicated that higher depression symptoms across time predicted an increase in the number of smoking peers, which in turn predicted smoking progression from mid-adolescence to late adolescence. In addition, smoking progression predicted a deceleration of depression symptoms from mid- to late adolescence. A significant indirect effect indicated that greater smoking at baseline predicted a deceleration in the number of smoking peers across time, which predicted a deceleration in depression symptoms from mid-adolescence to late adolescence. Conclusions The current study provides the first evidence of bidirectional self-medication processes in the relationship between adolescent smoking and depression and highlights peer smoking as one explanation for the comorbidity. [source] ,Agree with the king': Henry VII, Edmund Dudley and the strange case of Thomas SunnyffHISTORICAL RESEARCH, Issue 205 2006Mark R. Horowitz Although Richard Empson and Edmund Dudley were executed in 1510 in part for their rabid prosecution of written bonds, their activities at the time were only quietly recognized as part of a royal policy encouraged by Henry VII (1485,1509). Yet there has been little investigation into how these ministers went about mulcting the populace, beyond the vituperative reports of the London chronicles. The case of Thomas Sunnyff, which has not been analyzed or placed in the context of such activity, is a rare example of how Empson, Dudley and their minions went about their business. Using City, local and national documentation, the article uncovers what happened, why and how it reflected royal policy. [source] Reaching the population with dementia drugs: what are the challenges?INTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 7 2007Fiona E Matthews Abstract Background Systematic evidence became available in the late 1990s on efficacy of cholinesterase inhibitors (CHEIs) for patients with mild to moderate Alzheimer's disease (AD) and they began to be used sporadically. Since January 2001 UK based guidelines indicated that one of three cholinesterase inhibitors (CHEIs) could be prescribed for these patients. Since then the cost of prescription in England and Wales has risen. There has been little investigation of uptake at the population level. Objective To estimate the population uptake of CHEIs in a population based study of dementia spanning this period. Design Using data from a 10-year follow up and a later 12 year interview of the Medical Research Council Cognitive Function and Ageing Study (MRC CFAS), a UK population based longitudinal cohort study of people originally aged 65 years and above, we investigated who was taking CHEIs during the period 2001,2004. We sought information from respondents taking part in the study what medication they were taking on a regular basis. Results Only 12, of the 219 individuals who received a study diagnosis of dementia were prescribed CHEIs [5%, 95% Confidence Intervals (CI) 3%,9%]) in 2001/2003 and none of the 28 individuals with a study diagnosis of dementia (0%, 95% CI 0,18%) in 2004 were prescribed CHEIs. Uptake was biased towards individuals with more education and higher social class. Conclusions These data suggest that any impact on AD progression at the population level will be negligible as prescription of CHEIs and uptake in the age group at highest risk is so limited. There is little evidence that this has changed over time. Copyright © 2006 John Wiley & Sons, Ltd. [source] Global gene profiling reveals a downregulation of BMP gene expression in experimental atrophic nonunions compared to standard healing fracturesJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 7 2006Takahiro Niikura Abstract Nonunion is a challenging problem that may occur following certain bone fractures. However, there has been little investigation of the molecular basis of nonunions. Bone morphogenetic proteins (BMPs) play a significant role in osteogenesis. However, little is known about the expression patterns of BMPs in abnormal bone healing that results in nonunion formation. These facts prompted us to investigate and compare the gene expression patterns of BMPs and their antagonists in standard healing fractures and nonunions using rat experimental models. Standard closed healing fractures and experimental atrophic nonunions produced by periosteal cauterization at the fracture site were created in rat femurs. At postfracture days 3, 7, 10, 14, 21, and 28, total RNA was extracted from the callus of standard healing fracture and fibrous tissue of nonunion (n,=,4 per each time point and each group). Gene expression of BMPs, BMP antagonists, and other regulatory molecules were studied by methods including Genechip® microarray and real-time quantitative RT-PCR. Gene expression of BMP-2, 3, 3B, 4, 6, 7, GDF-5, 7, and BMP antagonists noggin, drm, screlostin, and BAMBI were significantly lower in nonunions compared to standard healing fractures at several time points. Downregulation in expression of osteogenic BMPs may account for the nonunions of fracture. The balance between BMPs and their endogenous antagonists is critical for optimal fracture healing. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:1463,1471, 2006 [source] Being a pretty good citizen: an analysis and monetary valuation of formal and informal voluntary work by gender and educational attainment1THE BRITISH JOURNAL OF SOCIOLOGY, Issue 1 2008Muriel Egerton Abstract This paper is set in the context of macrosocial/macroeconomic theories of the organization of both paid and unpaid work. The specific topic investigated is engagement in unpaid voluntary work, an activity which is thought to be important for social cohesion, civil society and citizenship. Research on the sources of social cohesion has focused on organizational membership and voluntary organization activity. There has been little investigation of informal helping of non-resident kin, friends or acquaintances, an activity which is not measured in most social surveys but is measured in time use surveys. Previous research shows that the highly educated are more likely to engage in formal voluntary organizations and data from the UK 2000 HETUS survey confirm that the highly educated spend more time on formally organised voluntary work. However, the less qualified, particularly women, spend more time on extra-household unpaid helping activities. Since both types of voluntary work are partly dependent on available time, these findings are modelled adjusting for time allocated to paid work, study, family and personal care. The findings remain statistically significant. Drawing on work carried out by the Office for National Statistics, a monetary value is placed on both formally organized and informal voluntary work. Although the median wage rates for formal voluntary work are greater than those for informal helping, the latter is greater in frequency and duration and therefore more economically valuable from a population perspective. This finding is discussed in the light of recent debates on citizenship and gender. [source] Constitutionalism and credibility in reforming economies1THE ECONOMICS OF TRANSITION, Issue 3 2006Raj M. Desai D72; D73; P20; P26 Abstract There has been relatively little investigation of the effect of constitutional transformations on the economic transition in post-communist countries. We develop a simple signalling model in which constitutionalism , a commitment to limit political power and provide judicial defence of basic rights , reinforces the credibility of pro-market candidates' electoral promises and boosts public support for economic reforms. These findings are tested using opinion poll data on public support for reform in Central and Eastern Europe, and in the former Soviet Union, in the 1990s. In a two-stage procedure we show that public support for market reforms is higher in countries where incumbents have taken deliberate steps to increase political accountability and judicial independence. Public support also spurs actual economic reform. [source] Use of real-time quantitative PCR to investigate root and gall colonisation by co-inoculated isolates of the nematophagous fungus Pochonia chlamydosporiaANNALS OF APPLIED BIOLOGY, Issue 1 2009S.D. Atkins Abstract The fungus Pochonia chlamydosporia is a potential biological control agent for plant parasitic nematodes, but to date, there has been little investigation of interactions (competitive, antagonistic or synergistic) between different isolates that occur together on roots and nematode galls. Real-time quantitative PCR (qPCR) has greatly improved the study of many fungi in situ on plant and nematode hosts, but distinguishing closely related isolates remains difficult. In this study, primers to discriminate P. chlamydosporia var. chlamydosporia and P. chlamydosporia var. catenulata were used to measure the relative abundance of isolates of the two varieties when inoculated singly or together on tomato plants. Also, sequence-characterised amplified polymorphic regions were identified to distinguish two different isolates of P. chlamydosporia var. chlamydosporia. Individual 1-cm root segments and nematode galls were excised, DNA extracted and subjected to real-time qPCR with the discriminatory primers. The qPCR method proved sensitive and reproducible and demonstrated that roots and nematode galls were not uniformly colonised by the fungi. Results indicated that the P. chalmydosporia var. catenulata isolate was more abundant on roots and eggs than P. chlamydosporia var. chlamydosporia, but all the isolates infected a similar proportion of nematode eggs. There was an indication that the abundance of each fungal isolate was reduced in co-inoculation experiments compared with single inoculations, but the number of root segments and galls colonised was not statistically significantly different. [source] | ||||||||||||||||