Lyme disease: self-regulation and pathogen invasion

Ecological interactions underlying the epidemic of Lyme disease involve a spirochete, a tick (with larval, nymph and adult stages), and two (or more) vertebrate hosts. Juvenile ticks ordinarily feed on mice; adult ticks feed on deer. Mice acquire the spirochete from infected nymphs and then pass the infection to larvae of the next tick generation. Lyme disease may result when a human is inadvertently bitten by an infectious nymph. Our model of the Lyme phenomenon counts the total number of ticks in each stage, the numbers of infected ticks by stage, and the number of infected mice. We fix the total population sizes of deer and mice, assume the ticks self-regulate, and solve the homogeneous-mixing case for equilibrium abundances. A local stability analysis identifies a condition where extinction of the spirochete is stable. Reversing this condition implies that the spirochete can invade the system of ticks and vertebrate hosts. When the spirochete can invade, a positive equilibrium number of infected organisms is locally stable. Spirochete invasion is promoted by a sufficient density of mice suffering low mortality, high susceptibility to infection in both mice and ticks, a high attack rate of ticks on mice, a high density of larval ticks, and low mortality among tick nymphs. Low mouse mortality allows the frequency of infection among nymphs to approach an individual tick's susceptibility when feeding on an infected mouse.     

Distribution and movement of infective-stage larvae of Dipetalonema viteae (Filarioidea) in the vector tick, Ornithodoros tartakowskyi (Argasidae)

To determine the behavior of Dipetalonema viteae in its tick vector, Ornithodoros tartakowskyi, the ticks were fed on jirds at successive intervals of 30 to 35 days after a single infective blood meal, and the number of larvae passing from the tick during each bite was determined by recovery of: 1) adult worms from the jirds' tissues; 2) larvae from skin snips taken at the feeding site immediately after the bite; and 3) larvae from serum and tissue after artificial feeding through a skin-membrane. All methods gave similar results. Ticks harboring few larvae released most of them (82%) during the first bite, and required only 2 bites to transmit all. Ticks with moderate or heavy infections required 3 or 4 bites to transfer all larvae. Factors which may explain this are: 1) relatively short duration of the bite of heavily infected ticks due to irritation and damage to the muscles of mouthparts and pharynx by the larvae; 2) resistance of the anterior alimentary tract to penetration by the larvae; and 3) retarding effects of crowding on development and migration of larvae. Aging of infection in the tick apparently did not influence the rate of transfer of larvae. Infection adversely affected the feeding and retarded the molting of young nymphs, but with the loss of larvae in successive bites the ability to suck blood was regained.     

Modeling the cross-sectional relationships between religion, physical health, social support, and depressive symptoms

The authors examined models of the relationships between religious activities, physical health, social support, and depressive symptoms in a sample of 4,000 persons age 65 and over. Religious activity was examined first as a single composite construct and then split into three component variables that were examined individually. Religious activity as a single construct was correlated with both social support and good physical health but was unrelated to depression. Split into the three components, model fit was significantly increased. Frequency of church attendance was positively related to physical health and negatively related to depression, but was surprisingly unrelated to social support. Frequent churchgoers were about half as likely to be depressed. Private prayer/Bible reading was negatively correlated with physical health and positively correlated with social support, but unrelated to depression. Religious TV/radio listening was unrelated to social support, negatively related to good physical health, and, unexpectedly, positively associated with depression.     

Perceived beneficial and detrimental postwar responses of Israeli adults: Are they positively or negatively linked to each other?

This study first compares two theoretical perspectives on the links between beneficial and detrimental posttraumatic responses. One group of studies claims that positive posttraumatic responses tend to be positively related with negative stress-related responses. Others posit that, after a severe stress, these responses are negatively correlated with each other. We argue that these contradictory results represent the different theoretical positions on the nature of favorable postwar outcomes. A second issue investigated is the associations of beneficial and detrimental postwar responses with demographic variables as well as with exposure to the stress of war. An Israeli adult sample (n = 870) was administered two different measures of negative posttraumatic outcomes (resource loss and postwar symptoms) and two different measures of positive posttraumatic outcomes (resource gains and posttraumatic recovery) one year after they were badly affected by a war. Resource gains correlated positively with resource loss, whereas PTR correlated negatively with postwar symptoms. There were also positive associations between the two measures of stress as well as the two beneficial posttraumatic outcomes. Older age, being a woman, lower economic status, and higher exposure to traumatic events tended to correlate positively with both measures of detrimental outcomes. These variables correlated negatively with PTR, and three of them (excluding economic status) were not significantly linked with resource gains. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The timing of color and location processing in the motor context

The contribution of migratory and resident birds to the introduction of Lyme disease will vary with the degree to which various species expose themselves to, and are infested by, juvenile vector ticks, and their ability to support and transmit the infectious agent. To examine the relative contribution of various passerine species during the emergence of this disease, we compared the abundance and infection rates of the blacklegged tick, Ixodes scapularis Say, removed from mist-netted birds with those from live-trapped mice at a coastal study site in southern Maine, collected during an 8-yr period in which the range of this tick and the incidence of Lyme disease increased in the state. Weekly bird-banding sessions using six 12-m Japanese mist nets were carried out from May through August 1989-1996. In 1989, 1991 and 1993, mice were live-trapped in a Sherman trap grid (7 by 7 m) during five 3-night sessions, June through August; in 1994-1996, 2 such grids were similarly trapped. Annual adult tick abundance was estimated by flagging vegetation. We removed 2,633 juvenile deer ticks from 1,713 of 1,972 birds examined. Twenty-five of 64 bird species were infested. The percentages of birds infested and the rate of infection among removed larvae and nymphs increased over the years, but species varied markedly in their ability to infect ticks. No infected larvae were removed from catbirds or towhees. The larval to nymphal ratio was higher in mice than in birds. Infection rates among bird-derived larvae were less than among mice-derived larvae, but increased with time. Because of the different ways in which individual species of passerine birds contribute to the availability of vector ticks and respond to the agent of Lyme disease in emerging areas, further research into host competency and borreliacidal mechanisms is needed.     

Observations on Onchocerca volvulus in experimentally infected chimpanzees

The paper describes observations made on 32 chimpanzees experimentally infected with Onchocerca volvulus. The mean pre-patent intervals for the Cameroon forest and the Guatemalan strains of O. volvulus were 13-16 months and 12-15 months respectively. That for the Cameroon Sudan-savanna strain was much longer, i.e. 22-23 months. The numbers of microfilariae found in the skins of animals infected with the Cameroon Sudan-savanna strain were also much lower than in animals infected with the other two strains. Long-term observations on infected animals showed that microfilarial infections had virtually died out 6.5-9 years after the last inoculation with infective larvae. Those animals which were inoculated with infective larvae in the head or above the waist tended to show a higher proportion of microfilariae in the upper parts of the body, than did those inoculated with infective larvae below the waist. In animals which showed adult worm-bundles on only one side of the body, the concentration of microfilariae was usually greater on that side of the body. Worm-bundles in the chimpanzee varied in size from 8 x 5 x 2 mm to 4 x 3 x 2 cm. Out of 47 worm-bundles found, only two were subcutaneous. The remainder lay deep in the tissues, most commonly adjacent to the posterior surface of the capsule of the hip joint. No onchocerciasis eye lesions were seen in any of the infected animals.     

Therapeutic and persistent efficacy of fipronil against Boophilus microplus (Acari: Ixodidae) on cattle

Cattle infested with all parasitic life-stages of Boophilus microplus (Canestrini) were treated once with a pour-on formulation of fipronil at 0.25, 0.5, or 1.0% active ingredient (AI) to determine the therapeutic efficacy. Additionally, cattle were infested at weekly intervals for 13 consecutive weeks after treatment to determine the persistent effectiveness of the three concentrations. Results of therapeutic efficacy of fipronil showed that with each increase in concentration there was a corresponding and often significant (P < 0.05) decrease in the numbers, fecundity and fertility of engorged females. The overall control of the Index of Reproduction (IR) achieved at 0.25 and 0.5% AI was 86.2 and 94.3%, respectively, while the control of the IR at the 1.0% AI concentration was 99.7%. The persistent efficacy of fipronil, like the therapeutic efficacy, was also dose related. The 0.25% AI treatment failed to provide complete protection (100%) against larval reinfestation, although control of the IR remained high (> 95%) for the first 6 weeks after treatment. In contrast, at 0.5% AI the control of the IR remained at 100% for the first 4 weeks after treatment, and was > 90% for an additional 2 weeks (6 weeks posttreatment). The 1.0% AI concentration afforded the longest residual activity, providing virtually 100% protection against larval reinfestation for 8 weeks after treatment was applied. Based on the results, neither the 0.25 or 0.5% AI concentration completely eliminated the immature stages of the tick (nymphs and larvae) on the host at the time of treatment (therapeutic efficacy), and the residual activity (persistent efficacy) did not prevent reinfestation by larvae for long periods after treatment. While the 1.0% AI concentration provided both therapeutic and residual efficacy that would be suitable for use in the eradication program, caution is still warranted because a few engorged females detached for up to 25 days after treatment, although none reproduced after the 6th day.     

Transformation of skin from larval to adult types in normally metamorphosing and metamorphosis-arrested salamander, Hynobius retardatus

Transformation of skin from larval to adult types in a salamander, Hynobius retardatus, which had been reported to show neotenic reproduction in a specific environment, was examined morphologically in normally metamorphosing, precociously metamorphosing and metamorphosis-arrested larvae. Typical larval skin was composed of an epidermis constituted by three types of cells such as apical, Leydig, and basal cells. The Leydig cells were larval specific, and thus disappeared and were replaced by adult epidermal cells during the metamorphosis. Disappearance of the Leydig cells was accomplished by apoptosis as confirmed by the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end-labeling method and electron microscopy during the normal metamorphosis and precocious metamorphosis induced by exogenously applied triiodothyronine. Typical adult skin was composed of epidermis constituted by stratified squamous cells and of dermis mainly occupied with two types of dermal glands, mucous and serous glands. When the metamorphosis was arrested by different procedures (thyroidectomy, hypophysectomy, goitrogen treatment, and rearing at low temperature), the larval-specific Leydig cells fully remained in the epidermis, suggesting that the disappearance of these depended on the thyroid activity. Contrary to this, dermal glands behaved differently from the Leydig cells, though they developed and differentiated from epidermal basal cells and constituted the same skin. Those in the metamorphosis-arrested (thyroidectomized, hypophysectomized, or goitrogen-treated) larvae, except in the larvae reared at 4 degrees C, appeared a little later than in the controls. Thus, the aged, metamorphosis-arrested larvae had skin which consisted of larval type epidermis (Leydig cells) and adult type dermis (mucous and serous glands).     

Survival, developmental and morphogenic deficiencies of Parasarcophaga argyrostoma (Diptera: Sarcophagidae) induced by the biosynthesis inhibitor, chlorfluazuron (IKI-7899)

To evaluate the activity of benzoylphenyl urea chitin biosynthesis inhibitor chlorfluazuron (IKI-7899) against Parasarcophaga argyrostoma, seven doses were topically applied (once) onto early third (last) instar larvae, puparia, or newly formed pupa: 150, 100, 50, 10, 1.0, 0.5, and 0.25 microgram/insect. After topical treatment of last instar larvae, the highest mortality was caused by both higher doses and the lowest mortality was caused by the lowest dose. The lethal activity of IKI-7899 as pronouncedly decreased as the treatment was lately carried out (at the puparial time). IKI-7899 failed to cause cumulative mortality because no pupal or adult mortalities were observed, irrespective of the time of treatment. Treated larvae suffered the action of IKI-7899 because they had decreased weight gain. Except the lowest dose, the weight gain of larvae inversely correlated with the dose-levels. IKI-7899 prolonged not only the larval duration but also the pupal duration after topical treatment of last instar larvae with doses 50-0.25 micrograms/larva. With no exception, all doses topically applied onto puparia or newly formed pupae enhanced pupae to live longer. Topical application onto last instar larvae resulted in different degrees of reduction of pupation rate, but IKI-7899 could not affect the pupal morphogenesis after larval treatment except by its highest dose which led to 8.33% pupal deformities and 7.69% larval-pupal intermediates. The dose 100 micrograms/larva topically applied onto last instar larvae detained 7.69% of what known as "permanent larvae" which suffered the action of the compound along 16 days and eventually perished without any external feature of puparium formation. A metamorphic effect of IKI-7899 pronouncedly appeared in the adult stage. Three higher doses completely arrested the adult flies. Topical application of the compound onto prepupae did not greatly reduce the pupation rate especially at the doses 50, 10 and 1.0 micrograms/puparium. The dose 50 micrograms/puparium was only the dose halting the pupal moulting program because 7.14% of permanent prepupae remained about 12 days and then died. In respect to adult emergence, the highest dose led to zero rate and the lowest dose allowed to all pupae to emerge without malformation.     

基于机器学习的薄板屈服强度与制耳率建模分析

针对1070铝合金薄板制耳率高、屈服强度不稳定等问题,基于生产数据,采用随机森林算法建立了“成分—工艺—性能”模型。选取冷轧率、热终轧温度、Fe含量、Fe/Si（铁硅质量比）等工艺和成分作为自变量,所建立的屈服强度模型精度（R2）为0.75,制耳率模型精度为0.87。利用模型定量分析各参数对屈服强度和制耳率的影响规律。通过对模型的解析,求解出各自变量的变量权重系数和Shap值。结果表明,对屈服强度影响最显著的因素为冷轧率,二者呈正相关关系,对制耳率影响最显著的因素为Fe含量,二者呈负相关关系。同时,根据模型进行了特定工艺下的性能预报并得出了较优工艺。      

Dermacentor hunteri (Acari: Ixodidae): seasonal variation in questing adults and on-host juvenile stages, and host associations and feeding behavior of larvae and nymphs

Dermacentor hunteri Bishopp is the only completely desert adapted tick in the Nearctic realm, and chiefly parasitizes desert bighorn sheep (Ovis canadensis Shaw) as an adult. The remainder of its life history has been unknown. We conducted field investigations in the Sonoran desert of the temporal and spatial variation of adult host-seeking ticks and of the host associations of juvenile ticks. Additionally, the feeding success of juvenile ticks was assessed in the laboratory. Adult ticks were found in significant numbers only in plateau and rocky slopes habitats, chiefly during the period from January to June. Questing adults were not found in July and August, and they were present in small numbers from September through December. Juvenile stages were found only on desert woodrats, Neotoma lepida Thomas (larvae and nymphs), and cactus mice, Peromyscus eremicus Baird (larvae only), in March, May, and early June. In the laboratory; both larvae and nymphs fed on N. lepida, but only larvae fed on P. maniculatus bairdii (Wagner). We concluded that the life history of D. hunteri may be constrained by the co-distribution of desert bighorn, desert woodrats, and perhaps cactus mice; and that adults oversummer either on desert bighorn or sequestered in favorable microclimates off the host.     

Dispositional mindfulness and depressive symptomatology: Correlations with limbic and self-referential neural activity during rest.

To better understand the relationship between mindfulness and depression, we studied normal young adults (n = 27) who completed measures of dispositional mindfulness and depressive symptomatology, which were then correlated with (a) rest: resting neural activity during passive viewing of a fixation cross, relative to a simple goal-directed task (shape-matching); and (b) reactivity: neural reactivity during viewing of negative emotional faces, relative to the same shape-matching task. Dispositional mindfulness was negatively correlated with resting activity in self-referential processing areas, whereas depressive symptomatology was positively correlated with resting activity in similar areas. In addition, dispositional mindfulness was negatively correlated with resting activity in the amygdala, bilaterally, whereas depressive symptomatology was positively correlated with activity in the right amygdala. Similarly, when viewing emotional faces, amygdala reactivity was positively correlated with depressive symptomatology and negatively correlated with dispositional mindfulness, an effect that was largely attributable to differences in resting activity. These findings indicate that mindfulness is associated with intrinsic neural activity and that changes in resting amygdala activity could be a potential mechanism by which mindfulness-based depression treatments elicit therapeutic improvement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The biological basis of grooming in moose: programmed versus stimulus-driven grooming

In domestic and wild mammals, tick infestation can be a significant fitness cost. Grooming behaviour has been shown to be effective in removing ticks. We studied grooming by moose, Alces alces, infested with winter ticks, Dermacentor albipictus, to determine which of two nonexclusive models for the regulation of tick-removal grooming, programmed or stimulus driven, best fit this host-parasite relationship. The programmed grooming model states that most grooming is driven by an internal timing mechanism which periodically evokes a bout a grooming independent of peripheral stimulation from tick bites. Because programmed grooming is preventive, the model predicts that those animals that groom the most will carry the fewest ticks, and a baseline level of programmed grooming is predicted even in a tick-sparse or tick-free environment. The stimulus-driven grooming model, on the other hand, states that grooming is a direct response to cutaneous irritation caused by tick bites and other sources of irritation. This stimulus-driven model predicts that (1) animals showing the highest rate of grooming will carry the most ticks and (2) animals will groom little when tick challenge is low. Both predictions of the stimulus-driven model were supported for moose: (1) calves oral-groomed three times more than cows, and tick densities on calves were three times higher than on cows; and (2) although all moose carried high densities of immature winter ticks (larvae, nymphs) from October through to February, grooming rate was very low until adult ticks started feeding in March-April. Peak grooming rates occurred during adult tick engorgement in March-April. Because an engorging adult female tick produces far more irritation than an engorging nymphal or larval tick, moose appeared to groom in direct proportion to the degree of cutaneous irritation and did not show a baseline level of grooming. The predominance of stimulus-driven grooming and apparent absence of programmed grooming may be the result of relaxed selection pressure for grooming in the evolutionary history of moose. Because the winter tick appears to have been introduced to moose from deer relatively recently, moose may not have had the time to adapt to winter ticks. The coevolutionary relationship between moose and winter ticks may be of insufficient duration for the evolution and/or maintenance of programmed grooming. (c) 1998 The Association for the Study of Animal Behaviour.     

The nephron microanatomy of the kidney in the lamprey Lampetra fluviatilis L. before and after metamorphosis

Isolated nephrons from premetamorphic lamprey larvae and adult animals were obtained using microdissection and kidney collagenase treatment methods. Significant differences in the architectonics of kidney tubules were found in larvae as compared with adults. The position of larval kidney was cranial while that in adult lampreys was caudal. The absence of nephron loop was noted in larval kidney. Distal and proximal tubules were shifted one from another in mediolateral direction. Distal tubule was significantly larger than proximal one. Mesonephric duct was located laterally near the glomus. Kidney tubules morphogenesis and nephron population number increase was observed at premetamorphic stage of larval kidney development.     

Transmission of Borrelia burgdorferi s.l. from mammal reservoirs to the primary vector of Lyme borreliosis, Ixodes ricinus (Acari: Ixodidae), in Sweden

Factors regulating prevalence of Borrelia burgdorferi s.l. Johnson, Schmid, Hyde, Steigerwalt & Brenner in Ixodes ricinus (L.) were examined during 1991-1992 at Bogesund, near Stockholm in south-central Sweden. Nine species of small and medium-sized mammals (Sorex araneus L., S. minutus L., Neomys fodiens Pennant, Clethrionomys glareolus [Schreber], Microtus agrestis [L.], Apodemus sylvaticus [L.], A. flavicollis [Melchior], Lepus europaeus Pallas, L. timidus L.) were found to infect feeding tick larvae with B. burgdorferi s.l., whereas two species of large mammals (Capreolus capreolus L., Alces alces L.) failed to infect feeding tick larvae with this spirochete. The most important mammalian reservoirs at the study locality were S. araneus and rodents, accounting for 91% of all I. ricinus larvae infected. In view of the great number of potentially effective reservoirs for B. burgdorferi s.l. in Sweden, control of Lyme disease by reduction of abundance of reservoir hosts will be difficult to achieve. We also found that infectivity of a rodent species is related to the number of infesting, potentially infective nymphal I. ricinus. Insectivores and rodents were the most important hosts of larval I. ricinus, whereas most nymphal ticks fed on hares and cervids. Adult I. ricinus were frequently found on all species of hares and cervids examined but never on insectivores and rodents. No single species seemed to be of paramount importance as a source of blood for female ticks. Therefore, control of Lyme disease by reduction of abundance of mammal hosts available for female tick engorgement will probably require massive reductions of numbers of both C. capreolus and L. timidus.     

Cyclin D1 expression in invasive breast cancer. Correlations and prognostic value

Cyclin D1 overexpression, detected by standard immunohistochemistry, was correlated with other prognostic variables and its prognostic value was evaluated in a group of 148 invasive breast cancers with long-term follow-up. Overexpression of cyclin D1 (59% of cases) was negatively correlated (chi 2 test) with histological grade (P = 0.0001), mean nuclear area (P = 0.004), mean nuclear volume (P = 0.02), and mitotic activity (P = 0.03) and positively correlated with estrogen receptor (P = 0.0001). There was a strong correlation between cyclin D1 overexpression and histological type (P = 0.0001). Positive cyclin D1 staining was seen in 11 of 13 tubular carcinomas, 3 of 3 mucinous carcinomas, 4 of 4 invasive cribriform carcinomas, and 17 of 20 lobular carcinomas. Of 102 ductal cancers, 52 were positive, and all 6 medullary carcinomas were negative. There were no significant correlations with lymph node status, tumor size, or DNA ploidy. In survival analysis, cyclin D1 overexpression did not provide significant univariate or multivariate prognostic value. In conclusion, cyclin D1 is mainly overexpressed in the well differentiated and lobular types of invasive breast cancer and is strongly associated with estrogen receptor positivity. It is negatively correlated with the proliferation marker mitoses count and with the differentiation markers nuclear area and nuclear volume. However, cyclin D1 overexpression does not seem to have prognostic value in invasive breast cancer when no adjuvant treatment is given.     

The association between daily stress and sexual activity.

Research has shown that stressors and experienced stress are negatively correlated with sexual activity (i.e., behavior and satisfaction) within couples. Thus far, most studies have been cross-sectional and report correlations only. This study is one of the first to examine the covariation between self-perceived stress and daily sexual activity within a time period of 3 months by collecting data on stress, sexual activity, sexual satisfaction, and sexual fulfillment as well as individual and dyadic coping. The association among these variables was tested in a multilevel model that included cyclical terms to capture the regular variation of sexual behavior over the days of the week. One hundred and three female students completed questionnaires and diaries 12 times during a 3-month period just prior to a major exam. Findings suggest that higher self-reported stress in daily life was associated with lower levels of sexual activity and satisfaction and a decrease in relationship satisfaction. In addition, dyadic coping was positively associated with sexual outcomes but did not moderate the association of experienced stress and sexuality. Implications for sexuality research in close relationships and methods for studying cyclical processes are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of Mesocyclops longisetus (Copepoda:Cyclopidae) on mosquitoes that inhabit tires: influence of litter type, quality, and quantity

A 59-week study was conducted to evaluate the impact of adult Mesocyclops longisetus populations on larval mosquito species inhabiting tires. Greater than 90% reduction of number of 1st and 2nd instars was recorded by 4 wk with 90% reduction of number of 3rd and 4th instars after 7 wk. Reduced control was noted with the onset of cooler winter water temperature. Overall. a 52% reduction in the number of 1st and 2nd instars was achieved, and a 57% reduction was noted in number of 3rd- and 4th-instar mosquito larvae. Cooler temperatures resulted in a decline of adult Mesocyclops, which resulted in reduced larval control. Significantly greater numbers of Mesocyclops adults were collected in tires with either new litter or heavy amounts of litter regardless of litter type. Lastly, litter type, either oak leaves or pine needles, did not influence mosquito reduction or abundance of Mesocyclops populations.     

Copper metabolism under the disturbed circulation of the liver (Eck''s fistula) in dogs. The relation between copper content and histologic changes in the brain (author''s transl)]

Resistance to the organophosphorus acaricides diazinon, dimethoate and formothion in the Biarra (B), Mackay (M) and Ridgelands (R) strains respectively of the cattle tick B. microplus has been shown previously to be controlled in each strain by a single incompletely dominant autosomal genetic factor. A very similar mode of inheritance of fenthion resistance in strain B has now been demonstrated with no departure in degree of dominance of resistance from the mean value of +0-57 common to these strains exposed to these chemicals. No F1 larval progeny from the following crossings were appreciably more resistant than their parents to these chemicals: R x B--bromophos ethyl and fenthion; B x M--carbaryl, chlorfenvinphos, chlorpyrifos, diazinon, dimethoate, ethion, fenthion and formothion; M x R--chlorfenvinphos, diazinon, dimethoate, ethion, formothion. The field importance of this absence of overdominance is discussed. There were no susceptible double recessive F2 larval progeny of B x M crossings of F2 or F3 larval progeny of R x M crossings when tested against dimethoate to which the three parental types were similarly resistant; 1/16 of the larval progeny would be expected to be completely susceptible if the resistance genes were unlinked. F1 adult progeny of B x M and R x M crossings exhibited the incompletely recessive mutant-type decreased brain acetylcholinesterase (AChE) activity common to strains B, M and R, thus satisfying the test for allelism. No ticks with normal levels of brain AChE were detected in F2 adult progeny of B x M or R x M crossings. This evidence was strongly suggestive of a series of closely linked genes or alleles controlling dimethoate resistance and a series of alleles controlling decreased brain AChE activity in strains B, M and R.     

Interpersonal workplace deviance: Why do offenders act out? A comparative look on personality and organisational variables.

To understand interpersonal workplace deviance in a more comprehensive way, in this study we investigated the relationship between personality and organisational variables. Hierarchical multiple regressions based on responses from 284 employees revealed that physical violence was positively related to continuance commitment and workplace frustration and negatively correlated with procedural justice. Also, psychological violence was negatively correlated with age but positively linked to affective commitment and frustration. Amongst personality traits, agreeableness was negatively correlated with both physical and psychological violence. Furthermore, personality traits still explained a statistically significant proportion of variance after controlling for organisational and sociodemographic factors. Thus, it seems imperative to include personality traits to fully understand interpersonal workplace deviance. The discussion aims to help organisations cope with deviance in their work environment. (PsycINFO Database Record (c) 2011 APA, all rights reserved)