Fourteen degrees of latitude and a continent apart: comparison of lichen activity over two years at continental and maritime Antarctic sites

There are marked declines in precipitation, mean temperatures and the number of lichen species with increasing latitude in Antarctica. However, it is not known which factors are the predominant controllers of biodiversity changes. Results are presented from over two years of almost continuous monitoring of both microclimate and activity in lichens at Livingston Island, South Shetland Islands, 62°S, and Botany Bay, Ross Sea region, 77°S. Lichen activity was evident over a much longer period at Livingston Island, (3694 versus 897 hours) and could occur in any month whereas it was almost completely confined to the period November–February at Botany Bay. Mean air temperatures were much lower at Botany Bay (-18° compared to -1.5°C at Livingston Island), but the temperatures at which the lichens were active were almost identical at around 2°C at both sites. When the lichens were active incident light at Botany Bay was very much higher. The differences are related to the availability of meltwater which only occurs at times of high light and warm temperatures at Botany Bay. Temperature as a direct effect does not seem to explain the differences in biodiversity between the sites, but an indirect effect through active hours is much more probable. In addition there are negative effects of stresses such as high light and extreme winter cold at Botany Bay

Photosynthetic performance of Xanthoria mawsonii C. W. Dodge in coastal habitats, Ross Sea region, continental Antarctica

Xanthoria mawsonii C. W. Dodge was found to perform well physiologically in a variety of habitats at high latitudes in continental Antarctica. The net photosynthetic rate of 7•5 μ mol CO2 kg−1 s−1 is exceptionally high for Antarctic lichens. Field and laboratory measurements proved the photosynthetic apparatus to be highly adapted to strong irradiance. The cold resistance of the photosystem II reaction centres is higher than the photosynthetic CO2 fixation process. Optimum temperature for net photosynthesis was c. 10°C. The lichen grows along water channels where it is frequently inundated and hydrated to maximum water content, although net photosynthesis is strongly depressed by super saturation. In these habitats the lichen is photosynthetically active for long periods of time. Xanthoria mawsonii also grows at sites where it depends entirely on the early spring snow melt and occasional snow fall for moisture. It has an exceptionally short reactivation phase and is able to utilize snow immediately. Recovery of activity by absorbing water vapour from air, though practically possible, seems to be of ecological importance only under snow at subzero temperatures

The moss Bryum argenteum var. muticum Brid. is well adapted to cope with high light in continental Antarctica

The net photosynthetic rate (NP), chlorophyll fluorescence, carotenoid content and chlorophyll content of the cosmopolitan moss Bryum argenteum were measured in the field at Botany Bay, southern Victoria Land, continental Antarctica (77°S). Comparisons were made between sun- and shade-adapted forms, and changes were followed as the moss emerged from under the snow and during exposure of shade and sun forms to ambient light. Shade forms had lower light compensation and saturation values for NP but little difference in maximal NP rates. Shade forms exposed to ambient light changed rapidly (within five days) towards the performance of the sun forms. Surprisingly, this change was not by acclimation of shoots but by the production of new shoots. Chlorophyll and carotenoid levels measured on a molar chlorophyll basis showed no difference between sun and shade forms and also little change during emergence. The constant molar relationship between carotenoids and chlorophyll plus the high levels of the xanthophyll cycle pigments suggest that protection of the chlorophyll antenna was constitutive. This is an adaptation to the very high light levels that occur when the plants are active in continental Antarctica and contrasts to the situation in more temperate areas where high light is normally avoided by desiccation

Zur Phototsynthese antarktischer Kryptogamen unter besonderer Berücksichtigung von Photoinhibition

In polar regions high quantum flux densities occur regularly during springtime and summer due to the high albedo of the persisting snowcover. Strong irradiances in the visible wavelength band are known to induce photoinhibition of photosynthesis. This factor could, therefore, be relevant for the primary productivity of mosses and lichens dominating the antarctic vegetation. Under controlled conditions in the laboratory a wide range of investigated species showed a reduced efficiency of photosystem II following an exposure to high quantum flux densities of 1500 µmol m-2 s-1. In mosses from shaded habitats like Pohlia cruda a treatment of two hours with strong light led to a reduction of gross photosynthesis and electron transport rate through photosystem II of 52%, that was not reversible within days. In the lichens Usnea aurantiaco-atra and Umbilicaria antarctica from dry, open exposed fellfield habitats even stronger effects were found. However, in the field these species experienced strong irradiance almost in the desiccated and highly resistant state only. Mosses as Sanionia uncinata, which dominate habitats with a constant water supply, did not desiccate in the field. Regularly occurring reductions of photosystem II efficiency in the field were quickly reversible. They seem to be part of protection mechanisms as the xanthophyll cycle that enable the organisms to perform photosynthesis at fluctuating light. The photosynthetic performance of all investigated organisms seems, therefore, to be well adapted to the light and temperature conditions in the antarctic summer

Photosynthetic responses of three common mosses from continental Antarctica

Predicting the effects of climate change on Antarctic terrestrial vegetation requires a better knowledge of the ecophysiology of common moss species. In this paper we provide a comprehensive matrix for photosynthesis and major environmental parameters for three dominant Antarctic moss species (Bryum subrotundifolium, B. pseudotriquetrum and Ceratodon purpureus). Using locations in southern Victoria Land, (Granite Harbour, 77°S) and northern Victoria Land (Cape Hallett, 72°S) we determined the responses of net photosynthesis and dark respiration to thallus water content, thallus temperature, photosynthetic photon flux densities and CO2 concentration over several summer seasons. The studies also included microclimate recordings at all sites where the research was carried out in field laboratories. Plant temperature was influenced predominantly by the water regime at the site with dry mosses being warmer. Optimal temperatures for net photosynthesis were 13.7°C, 12.0°C and 6.6°C for B. subrotundifolium, B. pseudotriquetrum and C. purpureus, respectively and fall within the known range for Antarctic mosses. Maximal net photosynthesis at 10°C ranked as B. subrotundifolium > B. pseudotriquetrum > C. purpureus. Net photosynthesis was strongly depressed at subzero temperatures but was substantial at 0°C. Net photosynthesis of the mosses was not saturated by light at optimal water content and thallus temperature. Response of net photosynthesis to increase in water content was as expected for mosses although B. subrotundifolium showed a large depression (60%) at the highest hydrations. Net photosynthesis of both B. subrotundifolium and B. pseudotriquetrum showed a large response to increase in CO2 concentration and this rose with increase in temperature; saturation was not reached for B. pseudotriquetrum at 20°C. There was a high level of variability for species at the same sites in different years and between different locations. This was substantial enough to make prediction of the effects of climate change very difficult at the moment

ST Quartz Acoustic Wave Sensors with Sectional Guiding Layers

We report the effect of removing a section of guiding layer from the propagation paths of ST-quartz Love wave sensors; this offers the ease of fabrication of a polymer guiding layer whilst retaining the native surface of the quartz which may then be used for the attachment of a sensitizing layer. Data is presented for rigid and viscous loading, which indicates a small reduction in mass sensitivity compared to a Love wave device. Biosensing capabilities of these discontinuous ‘sectional’ guiding layer devices are demonstrated using protein adsorption from solution

Macro- and Micronutrient Intake in Children with Avoidant/Restrictive Food Intake Disorder

Although case studies in avoidant/restrictive food intake disorder (ARFID) indicate severe nutritional deficiencies in those with a highly limited amount or variety of food intake, systematic analyses on food intake in treatment-seeking children and adolescents with ARFID are lacking. Within this study, n = 20 patients with an interview-based diagnosis of ARFID (0–17 years) were included and compared to n = 20 healthy controls individually matched for age and sex. Children or parents completed three-day food diaries and a food list. Macronutrient, vitamin, and mineral supply was determined based on the percentage of their recommended intake. The results showed a significantly lower total energy and protein intake in ARFID versus controls, with trends for lower fat and carbohydrate intake. ARFID subtypes of limited amount versus variety of food intake significantly differed in macro-, but not micronutrient intake. Those with ARFID met only 20–30% of the recommended intake for most vitamins and minerals, with significantly lower intake relative to controls for vitamin B1, B2, C, K, zinc, iron, and potassium. Variety of food intake was significantly reduced in ARFID versus controls in all food groups except carbohydrates. This study demonstrated that ARFID goes along with reduced everyday life macro- and micronutrient intake, which may increase the risk for developmental and health problems. Future studies additionally assessing serum nutrient levels in a larger sample may further explore differences in food intake across diverse ARFID presentations

Maternal sensitivity and intrusiveness in early childhood as predictors of children's weight at school age

Background While previous research indicates that low maternal sensitivity in mother-child interactions puts children at risk of overweight and obesity, maternal intrusiveness has rarely been investigated in association with children's weight. We investigated whether maternal sensitivity and intrusiveness in early childhood predict children's increased body mass index standard deviation scores (BMI-SDS) at school age. BMI-SDS are standardized for age and gender with respect to a reference standard. Methods At baseline (t1), we assessed maternal sensitivity and (non-)intrusiveness of 116 mothers with their children (48.3% female) aged 5–47 months (M = 24.00, SD = 11.36) using the emotional availability scales. We obtained anthropometric data for mothers at t1 by measuring height and weight in the laboratory and for children at birth assessed by medical staff. Six years later (t2) we obtained anthropometric data for children in the laboratory or based on parental report. Linear regression analyses were run with child BMI-SDS at t2 as outcome and sensitivity and (non-)intrusiveness as predictors, adjusting for confounders and exploring child age and gender as moderators. Results Maternal sensitivity only negatively predicted children's BMI-SDS in girls, while maternal intrusiveness predicted higher child BMI-SDS at school age regardless of child gender. The effect of maternal non-intrusiveness remained significant when controlling for confounders. Conclusion Maternal intrusiveness in early childhood seems to represent a risk factor for increased BMI-SDS in children, while lower maternal sensitivity tends to be a risk factor for increased BMI-SDS in girls. This may have implications for prevention or intervention programmes

Distribution and clinical comparison of restrictive feeding and eating disorders using ICD-10 and ICD-11 criteria.

OBJECTIVE Within the eleventh edition of the International Classification of Diseases (ICD-11), diagnostic criteria for feeding and eating disorders were revised and new diagnoses including avoidant/restrictive food intake disorder (ARFID) are classifiable; however, nothing is known about how these changes affect the prevalence of feeding and eating disorders. This study compared the distribution and clinical characteristics of restrictive feeding and eating disorders between ICD-10 and ICD-11. METHOD The Eating Disorder Examination (EDE), its child version, and the EDE ARFID module were administered to N = 82 patients (0-17 years) seeking treatment for restrictive feeding and eating disorders and their parents. Clinical characteristics were derived from medical records, questionnaires, and objective anthropometrics. RESULTS The number of residual restrictive eating disorders (rrED) significantly decreased from ICD-10 to ICD-11 due to a crossover to full-threshold disorders, especially anorexia nervosa (AN) or ARFID. Patients reclassified to ICD-11 ARFID were younger, had an earlier age of illness onset, more restrictive eating behaviors, and tended to have more somatic comorbidities compared to those reclassified to ICD-11 AN. Patients with rrED according to both ICD-10 and ICD-11 were younger, had an earlier age of illness onset, less shape concern, and more somatic comorbidities than patients who were reclassified from ICD-10 rrED to ICD-11 AN or ARFID. DISCUSSION This study highlights the inclusive approach of ICD-11 criteria, paving the way for more targeted treatment, and ARFID's high clinical relevance. Future studies considering nonrestrictive feeding and eating disorders across the life span may allow further analyses on diagnostic crossover. PUBLIC SIGNIFICANCE Changes in diagnostic criteria for restrictive eating disorders within the newly published ICD-11 led to an increase in full-threshold disorders, while the number of rrED was significantly lowered compared to ICD-10 criteria. The results thus highlight the diagnostic utility of ICD-11 criteria and may help providing adequate treatment to children and adolescents with rrED

SU-8 Guiding Layer for Love Wave Devices

SU-8 is a technologically important photoresist used extensively for the fabrication of microfluidics and MEMS, allowing high aspect ratio structures to be produced. In this work we report the use of SU-8 as a Love wave sensor guiding layer which allows the possibility of integrating a guiding layer with flow cell during fabrication. Devices were fabricated on ST-cut quartz substrates with a single-single finger design such that a surface skimming bulk wave (SSBW) at 97.4 MHz was excited. SU-8 polymer layers were successively built up by spin coating and spectra recorded at each stage; showing a frequency decrease with increasing guiding layer thickness. The insertion loss and frequency dependence as a function of guiding layer thickness was investigated over the first Love wave mode. Mass loading sensitivity of the resultant Love wave devices was investigated by deposition of multiple gold layers. Liquid sensing using these devices was also demonstrated; water-glycerol mixtures were used to demonstrate sensing of density-viscosity and the physical adsorption and removal of protein was also assessed using albumin and fibrinogen as model proteins