title: Influence of hygrothermal ageing on the physico-mechanical properties of alkali treated industrial hemp fibre reinforced polylactic acid composites

authors: Islam, Mohammad Saiful

subjects: hemp fibre

abstract: 30 wt% aligned untreated long hemp fibre/polylactic acid (AUL) and aligned alkali treated long hemp fibre/polylactic acid (AAL) composites were produced by film stacking and subjected to hygrothermal ageing environment along with neat polylactic acid (PLA). Hygrothermal ageing was carried out by immersing samples in distilled water at 25 and 50 ºC over a period of 3 months. It was found that both neat PLA and composites followed Fickian diffusion. Higher temperature generally increased the Diffusion coefficient, D of neat PLA and composites, as well as shortening the saturation time. Neat PLA had the lowest D value followed by AAL composites and then AUL composites. After hygrothermal ageing, tensile and flexural strength, Young’s and flexural modulus and KIc were found to decrease and impact strength was found to increase for both AUL and AAL composites. AUL composites had greater overall reduction in mechanical properties than that for AAL composites after hygrothermal ageing. Crystallinity contents of the hygrothermal aged composites support the results of the deterioration of mechanical properties upon exposure to hygrothermal ageing environment.

text: Influence of hygrothermal ageing on the physico-mechanical properties of alkali treated industrial hemp fibre reinforced polylactic acid composites 30 wt% aligned untreated long hemp fibre/polylactic acid (AUL) and aligned alkali treated long hemp fibre/polylactic acid (AAL) composites were produced by film stacking and subjected to hygrothermal ageing environment along with neat polylactic acid (PLA). Hygrothermal ageing was carried out by immersing samples in distilled water at 25 and 50 ºC over a period of 3 months. It was found that both neat PLA and composites followed Fickian diffusion. Higher temperature generally increased the Diffusion coefficient, D of neat PLA and composites, as well as shortening the saturation time. Neat PLA had the lowest D value followed by AAL composites and then AUL composites. After hygrothermal ageing, tensile and flexural strength, Young’s and flexural modulus and KIc were found to decrease and impact strength was found to increase for both AUL and AAL composites. AUL composites had greater overall reduction in mechanical properties than that for AAL composites after hygrothermal ageing. Crystallinity contents of the hygrothermal aged composites support the results of the deterioration of mechanical properties upon exposure to hygrothermal ageing environment.

year: 2010

title: Parent mental health and associations with mind-mindedness across two  infant interactions: free play and a teaching task

authors: Sparrow, Kerry

subjects: Parental mental health

abstract: Mind-mindedness (MM) is the tendency of a parent to recognise and treat their child as having a mind of their own. The current study aimed to examine associations of parent mental health and wellbeing symptoms with parental MM across two infant interactions: a free play and a teaching task. Sixty-two parent-infant dyads from New Zealand and Australia participated in the interactions, which were recorded and then coded for positive and negatively valenced appropriate and non-attuned MM. In addition, parents also completed the Depression, Anxiety and Stress Scale (DASS-21; Lovibond & Lovibond, 1995), the Difficulties with Emotion Regulation Scale (DERS; Gratz & Roemer, 2004) and the Parental Reflective Functioning Questionnaire (PRFQ; Luyten, Mayes, Sadler, Fonagy, Nicholls, Crowley & Slade, 2009) via an online survey. 
The results showed that the proportion of appropriate positive MM comments differed across the tasks. Parents spoke more overall during free play but made more appropriate positive and negative comments in the teaching task.  Greater parental stress and anxiety symptoms were associated with more appropriate negative mind-minded comments, with different patterns seen across the two tasks. In free play, stress was associated with appropriate negative MM; whereas in the teaching task, greater parent stress and anxiety were associated with more appropriate negative MM and fewer non-attuned MM comments. Appropriate and non-attuned MM comments were positively correlated with parental pre-mentalising. Increased parental difficulties with emotional regulation were linked to an increase in appropriate negative and also non-attuned MM comments. Stress explained 11.7% of the variance in appropriate negative MM comments in free play, and anxiety explained 12.1% of the variance in appropriate negative MM during the teaching task. Stress and PRFQ pre-mentalising together explained 23.2% of the variance in non-attuned MM comments in the teaching task 
The current findings have implications for understanding how parental wellbeing is associated with differences in MM and extend existing research from free play contexts to the parent-infant teaching context. Understanding differences in MM as a function of parent mental health is important in targeting future MM interventions to support high-risk parents. This research was conducted over the COVID period with varying impacts. In particular, DERS and DASS scores were higher than other research conducted prior to COVID, so caution is required when considering the generalisability of the results. However, this may reflect the ‘new normal’ for a significant portion of time as COVID impact has been reported to be significant and ongoing.

text: Parent mental health and associations with mind-mindedness across two  infant interactions: free play and a teaching task Mind-mindedness (MM) is the tendency of a parent to recognise and treat their child as having a mind of their own. The current study aimed to examine associations of parent mental health and wellbeing symptoms with parental MM across two infant interactions: a free play and a teaching task. Sixty-two parent-infant dyads from New Zealand and Australia participated in the interactions, which were recorded and then coded for positive and negatively valenced appropriate and non-attuned MM. In addition, parents also completed the Depression, Anxiety and Stress Scale (DASS-21; Lovibond & Lovibond, 1995), the Difficulties with Emotion Regulation Scale (DERS; Gratz & Roemer, 2004) and the Parental Reflective Functioning Questionnaire (PRFQ; Luyten, Mayes, Sadler, Fonagy, Nicholls, Crowley & Slade, 2009) via an online survey. 
The results showed that the proportion of appropriate positive MM comments differed across the tasks. Parents spoke more overall during free play but made more appropriate positive and negative comments in the teaching task.  Greater parental stress and anxiety symptoms were associated with more appropriate negative mind-minded comments, with different patterns seen across the two tasks. In free play, stress was associated with appropriate negative MM; whereas in the teaching task, greater parent stress and anxiety were associated with more appropriate negative MM and fewer non-attuned MM comments. Appropriate and non-attuned MM comments were positively correlated with parental pre-mentalising. Increased parental difficulties with emotional regulation were linked to an increase in appropriate negative and also non-attuned MM comments. Stress explained 11.7% of the variance in appropriate negative MM comments in free play, and anxiety explained 12.1% of the variance in appropriate negative MM during the teaching task. Stress and PRFQ pre-mentalising together explained 23.2% of the variance in non-attuned MM comments in the teaching task 
The current findings have implications for understanding how parental wellbeing is associated with differences in MM and extend existing research from free play contexts to the parent-infant teaching context. Understanding differences in MM as a function of parent mental health is important in targeting future MM interventions to support high-risk parents. This research was conducted over the COVID period with varying impacts. In particular, DERS and DASS scores were higher than other research conducted prior to COVID, so caution is required when considering the generalisability of the results. However, this may reflect the ‘new normal’ for a significant portion of time as COVID impact has been reported to be significant and ongoing.

year: 2023

title: Radiocarbon dates on desiccated moa (Dinornithiformes) flesh from Inland Otago, New Zealand

authors: Anderson, Atholl

subjects: New Zealand

abstract: Remains of soft tissues from extinct moa (Dinornithiformes), mainly desiccated sinew, muscle, skin, and feathers have been recovered rather seldom but their distribution is distinctive. Of 22 records of such finds accumulated between 1864 and 1987, 15 came from inland Otago (Anderson 1989: 67–68, Table 5.2), west of Dunedin in the southern South Island. Most were found in the late nineteenth century (13 records) in rockshelters, clefts or alluvial sediments and were regarded at the time as evidence of the survival of moa up to about AD 1800 (Hutton and Coughtrey 1874a). Improbable as this latter point is, it has not been tested by radiocarbon dating until now. Our particular impetus to do so, however, arises in another way. It is from research, again largely within inland Otago, on Maori artefacts which have also been made from various other kinds of soft tissues (flax, grasses, dog skin, bird skin, feathers etc.). A series of accelerator mass spectrometry (AMS) radiocarbon dates on these (Anderson et al., n.d.) shows that they are exclusively late, post-AD 1650, which begs the question of why the age range does not extend across the full prehistoric period, beginning about AD 1300.

text: Radiocarbon dates on desiccated moa (Dinornithiformes) flesh from Inland Otago, New Zealand Remains of soft tissues from extinct moa (Dinornithiformes), mainly desiccated sinew, muscle, skin, and feathers have been recovered rather seldom but their distribution is distinctive. Of 22 records of such finds accumulated between 1864 and 1987, 15 came from inland Otago (Anderson 1989: 67–68, Table 5.2), west of Dunedin in the southern South Island. Most were found in the late nineteenth century (13 records) in rockshelters, clefts or alluvial sediments and were regarded at the time as evidence of the survival of moa up to about AD 1800 (Hutton and Coughtrey 1874a). Improbable as this latter point is, it has not been tested by radiocarbon dating until now. Our particular impetus to do so, however, arises in another way. It is from research, again largely within inland Otago, on Maori artefacts which have also been made from various other kinds of soft tissues (flax, grasses, dog skin, bird skin, feathers etc.). A series of accelerator mass spectrometry (AMS) radiocarbon dates on these (Anderson et al., n.d.) shows that they are exclusively late, post-AD 1650, which begs the question of why the age range does not extend across the full prehistoric period, beginning about AD 1300.

year: 2010