Associations between childhood adversity, cognitive schemas and attenuated psychotic symptoms

Aim: Childhood Adversity (CA) is strongly linked to psychotic-like symptoms across the clinical spectrum, though the mechanisms underlying these associations remain poorly understood. Negative cognitive schemas are associated with both CA exposure and psychotic symptoms, highlighting the possibility that cognitive schemas may be a key risk pathway. The purpose of this study was to determine whether negative cognitive schemas mediate the association between CA and specific attenuated psychotic symptoms in a large sample of clinical-high risk youth. Given the variability in experiences that encompass CA (eg, abuse, neglect and poverty) and attenuated psychotic symptoms (eg, suspiciousness and perceptual abnormalities), we also tested whether these associations differ by CA type (threat vs deprivation) and attenuated positive psychotic symptom domain. Methods: Data were collected from 531 clinical-high risk youth between 12 and 35 years of age (mean = 18.80, SD = 4.21) who completed a clinical assessment that included the Structured Interview of Prodromal Syndromes (SIPS), Childhood Trauma and Abuse scale and questionnaires on cognitive schemas and depressive symptoms. Results: No direct effects of threat or deprivation exposure on any of the psychotic symptom domains were found. However, there was a unique indirect effect of threat, but not deprivation, on delusional thinking and suspiciousness through negative cognitive schemas about others. Conclusion: Cognitive vulnerability in the form of negative schemas about others may be one mechanism linking childhood threat experiences and attenuated psychotic symptoms. The results underscore the importance of targeting negative schemas in interventions to mitigate psychosis risk

Virus infection and grazing exert counteracting influences on survivorship of native bunchgrass seedlings competing with invasive exotics

1.  Invasive annual grasses introduced by European settlers have largely displaced native grassland vegetation in California and now form dense stands that constrain the establishment of native perennial bunchgrass seedlings. Bunchgrass seedlings face additional pressures from both livestock grazing and barley and cereal yellow dwarf viruses (B/CYDVs), which infect both young and established grasses throughout the state. 2.  Previous work suggested that B/CYDVs could mediate apparent competition between invasive exotic grasses and native bunchgrasses in California. 3.  To investigate the potential significance of virus-mediated mortality for early survivorship of bunchgrass seedlings, we compared the separate and combined effects of virus infection, competition and simulated grazing in a field experiment. We infected two species of young bunchgrasses that show different sensitivity to B/CYDV infection, subjected them to competition with three different densities of exotic annuals crossed with two clipping treatments, and monitored their growth and first-year survivorship. 4.  Although virus infection alone did not reduce first-year survivorship, it halved the survivorship of bunchgrasses competing with exotics. Within an environment in which competition strongly reduces seedling survivorship (as in natural grasslands), virus infection therefore has the power to cause additional seedling mortality and alter patterns of establishment. 5.  Surprisingly, clipping did not reduce bunchgrass survivorship further, but rather doubled it and disproportionately increased survivorship of infected bunchgrasses. 6.  Together with previous work, these findings show that B/CYDVs can be potentially powerful elements influencing species interactions in natural grasslands. 7.  More generally, our findings demonstrate the potential significance of multitrophic interactions in virus ecology. Although sometimes treated collectively as plant ‘predators’, viruses and herbivores may exert influences that are distinctly different, even counteracting

Uroleucon formosanum (Takahashi) (Homoptera: Aphididae) Found on Youngia japonica (L.) DC on Guam and Rota in the Mariana Islands

Scientific note.Uroleucon formosanum (Homoptera: Aphididae) was collected from Asiatic (Oriental) hawksbeard, Youngia japonica, on Guam and Rota in 2003. These collections constitute a significant range expansion for U. formosanum into the western Pacific region. The aphid and its host plant were likely accidentally introduced to the islands in cargo or by travelers returning from known host regions in eastern Asia and Japan

Uroleucon formosanum (Takahashi) and Uroleucon sonchellum (Monell) (Hemiptera, Aphididae): Morphological Comparison and Diagnosis

Uroleucon formosanum (Takahashi) and U. sonchellum (Monell) (Hemiptera: Aphididae: Aphidinae: Macrosiphini) are species of very similar morphology. Descriptions, illustrations, morphological measurements and a diagnosis are provided