Calving is a complex process subject to several cooperating atmospheric, oceanographic and glaciological forcings that vary in space and time, and whose relative effects are challenging to separate. Statistical ‘Systems Analysis’ is commonly used in engineering and economics to extricate complex ‘force–response’ relationships. Here we apply Systems Analysis to the Amery rift system, East Antarctica. We develop a scalable ‘System Model’ driven by a coarsely-sampled dataset characteristic of glaciological observations in remote locations, and validate it using rift lengths observed in 2000–06 and 2012. In this initial demonstration, we forecast a detachment date of ~2019 ± 5 years for the large tabular iceberg colloquially known as the ‘Loose Tooth’, for which relative humidity surprisingly emerges as the best statistical predictor. RACMO2 climate modelling reveals that relative humidity correlates best with surface albedo and snowmelt, both of which are intimately linked to firn compaction and ice shelf temperature and flow. We postulate that relative humidity can therefore serve as a proxy for internal stress, a known key control of ‘Loose Tooth’ calving. Although no physical causality is implied in Systems Analysis, postulates such as this can aid in setting priorities in studies of complex glaciological processes.

On tests of design fluency, an examinee draws as many different designs as possible in a specified time limit while avoiding repetition. The neuroanatomical substrates and diagnostic group differences of design fluency repetition errors and total correct scores were examined in 110 individuals diagnosed with dementia, 53 with mild cognitive impairment (MCI), and 37 neurologically healthy controls. The errors correlated significantly with volumes in the right and left orbitofrontal cortex (OFC), the right and left superior frontal gyrus, the right inferior frontal gyrus, and the right striatum, but did not correlate with volumes in any parietal or temporal lobe regions. Regression analyses indicated that the lateral OFC may be particularly crucial for preventing these errors, even after excluding patients with behavioral variant frontotemporal dementia (bvFTD) from the analysis. Total correct correlated more diffusely with volumes in the right and left frontal and parietal cortex, the right temporal cortex, and the right striatum and thalamus. Patients diagnosed with bvFTD made significantly more repetition errors than patients diagnosed with MCI, Alzheimer's disease, semantic dementia, progressive supranuclear palsy, or corticobasal syndrome. In contrast, total correct design scores did not differentiate the dementia patients. These results highlight the frontal-anatomic specificity of design fluency repetitions. In addition, the results indicate that the propensity to make these errors supports the diagnosis of bvFTD. (JINS, 2012, 18, 1–11)

Field experiments were conducted to study the effects of oxadiazon and oxyfluorfen on weeds and Syrian marjoram (Origanum syriacum L.) in the central Jordan Valley during the period from 1998 to 2001. Results showed that weed competition with marjoram for the whole growing period resulted in almost complete crop failure. Oxyfluorfen and oxadiazon applied preplanting or postplanting to marjoram controlled weeds effectively, resulted in significant increase in marjoram shoot fresh and dry weight yields and in more branches per plant compared with the weed-infested control. High marjoram yield was obtained with oxyfluorfen applied at 0.72 kg ai/ha in preplanting treatment and with oxadiazon at 1.25 and 0.75 kg ai/ha in pre- and postplanting treatments, respectively. In preplanting treatment, 0.36 kg ai/ha of oxyfluorfen was highly selective, but 1.44 kg ai/ha reduced marjoram yield. Conflicting results were obtained with oxadiazon under the same treatments. In postplanting, oxyfluorfen at 0.24 and 0.96 kg ai/ha significantly increased marjoram yield over the weed-infested control. However, the highest shoot dry weight of marjoram was obtained at 0.96 kg ai/ha of this herbicide. In contrast, the low rate (0.38 kg ai/ha) of oxadiazon was highly selective and increased marjoram yield, but the herbicide failed to increase yield beyond the weed-infested control when the higher rate (1.5 kg ai/ha) was used. Results showed that both oxyfluorfen and oxadiazon herbicides were highly selective and effective for weed control in Syrian marjoram, providing normal rates of both are used, although high rates of the two herbicides were also selective and increased marjoram yield over the weed-infested control.

Several weed species have been reported to have allelopathic activities. However, most of these studies indicate the probable involvement of allelochemicals but are not conducted in field settings. In addition to their adverse effects on growth and yield of many crop species, many troublesome weeds such as mugwort and lantana influence biodiversity. More studies on the ecological, physiological, and molecular aspects of weed allelopathy should be conducted in order to better understand community structure and declining biodiversity.

The number of papers published on allelopathy was low until the 1970s but has accelerated rapidly in recent years. Alleged allelopathic activity has been suggested for numerous weed and crop species; however, many studies employed preliminary bioassays (leachates or extracts in the absence of soil). The importance of substratum and of abiotic and biotic stresses (nutrients, shade, herbides, plant diseases, herbivores), plant density, habitat, and climate has been realized in recent years. Laboratory bioassay, the first step to investigate probable involvement of allelopathy, should be designed to correspond to field conditions. Studies need to focus on the effects of (1) climatic, environmental, and habitat factors on allelopathic potential; (2) abiotic and biotic soil components on fate and biological activity of allelochemicals; and (3) allelochemicals on soil nutrient dynamics, microbial ecology, and other abiotic and biotic components. Recently, attempts to find crop cultivars with a competitive allelopathic edge have been made. Interaction of professionals from different disciplines is needed to understand the complexity of the ecosystem. The following are important topics for discussion: allelopathy and the transition to sustainable agriculture; physiological and biochemical studies; using transgenes to produce allelopathic crops; microbial allelochemicals and pathogens as weed biological agents; bioassays for allelopathy (problems and solutions); pollen allelopathy; and an ecological perspective of allelopathy.

How surfactants modify the characteristics of a spray liquid is now reasonably well understood. Beneficial effects are primarily associated with reduction in surface tension. However, the mechanisms whereby surfactants enhance the diffusion of herbicides across the plant cuticle are less clear. Generally, hydrophilic surfactants with a high hydrophile/lipophile balance (HLB) are most effective at enhancing penetration of herbicides with high water solubility, whereas lipophilic surfactants with a low HLB are most effective for enhancing uptake of herbicides with low water solubility. Both high- and low-HLB surfactants are absorbed into the cuticle, but current theory suggests different mechanisms are involved in enhancing diffusion of hydrophilic and lipophilic herbicides across the cuticle. Surfactants having a high HLB are absorbed into the cuticle and enhance the water-holding capacity (hydration state) of the cuticle. With increased cuticle hydration, the permeance of hydrophilic herbicides into the cuticle is increased, which increases the herbicide diffusion rate at a constant concentration gradient. Surfactants having a low HLB are absorbed into the cuticle and increase the fluidity of waxes, as measured by a small reduction in melting point. This increased fluidity increases the permeance of lipophilic herbicides in the cuticle, which, in turn, increases their diffusion rate at a set concentration gradient.

Adjuvant research contributes much to the knowledge and practice of weed science though the scientific process of systematically asking precise questions and subsequently making distinctions among alternative explanations. The purpose of adjuvant experimentation is to answer these questions and the purpose of associated papers and presentations is to communicate the new information. These purposes are self-evident, but are difficult to perfect. Some factors are particularly difficult for adjuvant researchers and require that researchers plan thoroughly from the formulation of the experimental question to final presentation of results. Adjuvant research requires both chemical and biological expertise that is traditionally separated in most organizations. Scientists from other disciplines or weed scientists not primarily concerned with adjuvants often direct adjuvant studies. This paper discusses mistakes that are commonly made in test design, interpretation, and presentation and suggests guidelines to improve the quality of adjuvant research.