832 research outputs found

    Land Tenure and the Management of Land Resources in Trinidad and Tobago

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    The potential of the agricultural sector in Trinidad and Tobago has not been realized in recent decades. The more productive land resources of the country are underutilized, while many of the more fragile ecosystems are in danger. This threatens to deny the country potential income from ecotourism as well as deprive future generations of a stable land, forest, and water base. The optimal use of the country's land resources requires a stable and secure tenure system defining land rights. The Government of the Republic of Trinidad and Tobago contracted the Land Tenure Center to carry out land rationalization studies, which are intended to assist in the preparation of an action plan to deal with the problems of the land tenure system. The result was the preparation of twenty-one studies, which have been organized into two LTC research papers. This first paper explores the nature and extent of tenure insecurities in both urban and rural contexts, with a focus on agricultural land tenure problems. Several hypotheses are advanced concerning the possible constraints that legal and social insecurity of tenure pose for the future development of the country. Also explored are the environmental problems that past tenure regimes have helped generate, and what might comprise a strategy for protecting fragile ecosystems. A second paper (LTC Research Paper 116) will dig more deeply into the institutional and historical roots of the tenure insecurity problems. A final report presented to the government in August 1992 described a Land Rationalization and Development Programme, which was derived from the twenty-one studies carried out by LTC.Land Economics/Use,

    AN INTERACTIONIST APPRAISAL OF IMPRESSION FORMATION: The "Central Trait" Hypothesis Revisited

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    This article examines the nature of first impressions from the interactionist perspective. A modified H. H. Kelley design (1950) of student-teacher interaction was employed with a sample of 195 college students. The fi ndi ngs demonstrate the overall complexi ty of the impressi on-form ing process as we II as i IIustrate the Ii mitations of the warm-cold variable in predicting actual behcvior , Several central traits are observed to be operative in impression formation. These traits are observed to be a function both of preinformation and response alternatives in the odjecrive checklist, Symbolic and observational presentation is found to be more influencial in forming impressions with behavioral implications than those formed solely by observational exposure. Both consideration of the context of interaction and central trait identification appear necessary to specify the behavioral component of impressions.http://web.ku.edu/~starjrn

    Bovine herpesvirus type-1 glycoprotein K (gK) interacts with UL20 and is required for infectious virus production

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    © 2016 We have previously shown that the HSV-1 gK and UL20 proteins interact and function in virion envelopment, membrane fusion, and neuronal entry. Alignment of the predicted secondary structures of gKs encoded by BoHV-1, HSV-1, HSV-2, EHV-1 and VZV indicated a high degree of domain conservation. Two BoHV-1 gK-null mutant viruses were created by either gK gene deletion or stop codon insertion. In addition, a V5 epitope-tag was inserted at the carboxyl terminus of gK gene to detect gK. The engineered gK-null mutant viruses failed to replicate and produce viral plaques. Co-immunoprecipitation of gK and UL20 expressed via different methods revealed that gK and UL20 physically interacted in the presence or absence of other viral proteins. Confocal microscopy showed that gK and UL20 colocalized in infected cells. These results indicate that BoHV-1 gK and UL20 may function in a similar manner to other alphaherpesvirus orthologues specified by HSV-1, PRV and EHV-1

    A critique and integration of the major social psychological approaches to the study of coalition formation

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    http://web.ku.edu/~starjrn

    Effects of transition metals on thermal properties of ZrB2

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    Nominally phase pure zirconium diboride ceramics were synthesized to study their intrinsic thermal properties. Ceramics for this study were synthesized by reaction hot pressing of reactor grade ZrH2 and B to minimize impurities commonly found in commercial powders such as the natural abundance (1-4 wt%) of Hf. Starting powders contained \u3c200 ppm Hf. Previous results showed that Hf impurities present in quantities comparable to commercial powders masked the effect of other transition metal additions. For example, additions of 3 at% Ti and Y had no apparent effect on thermal conductivity of ceramics produced from commercial ZrB2. Lowering the Hf content to 0.4 at% increased thermal conductivity from ~90 W/m•K for ZrB2 ceramics prepared from commercial powders to ~100 W/m•K for low-Hf content ZrB2 at 25 °C. Lowering the Hf content also increased the thermal conductivity at 2000°C from ~70 W/m•K to ~80 W/m•K. For the low Hf ZrB2, adding 3 at% TiB2 decreased thermal conductivity ~15 W/m•K at 25°C while adding 3 at% MoB2 decreased thermal conductivity ~45 W/m•K at 25°C. For the present study, transition metals such as Hf, Ti, Y, Ta, and W were added individually to nominally phase pure ZrB2 to study the effects on thermal diffusivity, thermal conductivity and heat capacity at temperatures from 25°C to 2000°C. These properties will be compared to values obtained for ceramics prepared from commercial ZrB2 powders, which contained the natural abundance of Hf. Most previous reports have relied on heat capacity values from the NIST-JANAF thermodynamic tables to calculate thermal conductivity of ZrB2 ceramics. However, the heat capacity of ZrB2 with low Hf content was approximately 10% greater than widely accepted values. Due to this difference, heat capacity will be measured for each composition, and these values will be used to calculate thermal conductivity. The intrinsic thermal properties of ZrB2will be discussed as well as the effect of transition metal additions on the thermal properties of ZrB2 with low and naturally abundant quantities of Hf

    Clinical and behavioural features of SYNGAP1-related intellectual disability: a parent and caregiver description

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    BACKGROUND: SYNGAP1-related intellectual disability (ID) is a recently described neurodevelopmental disorder that is caused by pathogenic variation in the SYNGAP1 gene. To date, the behavioural characteristics of this disorder have mainly been highlighted via the prevalence of existing diagnoses in case series. We set out to detail the behavioural features of this disorder by undertaking interviews with those who have a child with SYNGAP1-related ID to allow them to describe their child’s behaviour. METHODS: We conducted 27 semi-structured interviews with parents and caregivers which covered basic information (e.g., age, gender), family history, perinatal history, past medical history, developmental history, epilepsy, behavioural history, and a general description of their child’s behaviour. RESULTS: Using a mixed quantitative and qualitative approach, the responses from the parents indicated that those with SYNGAP1-related ID showed high rates of autism spectrum disorder (52%), difficulties with fine and gross motor skills, delays in language development, and a high prevalence of epilepsy (70%). A qualitative analysis highlighted their general behaviour affected the themes of daily living skills, distress-related behaviours, emotional regulation, difficulties with change, a lack of danger awareness, and sensory differences. Sensory features described involved auditory, visual, tactile, gustatory, and proprioceptive themes. CONCLUSIONS: Our findings and behavioural descriptions provide important insights as well as implications for the diagnosis and care of those with SYNGAP1-related ID. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s11689-022-09437-x

    Visual social attention in SYNGAP1-related intellectual disability

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    SYNGAP1-ID is a neurodevelopmental disorder caused by a mutation of the SYNGAP1 gene. Characterized by moderate to severe developmental delay, it is associated with several physical and behavioral issues as well as additional diagnoses, including autism. However, it is not known whether social cognitive differences seen in SYNGAP1-ID are similar to those previously identified in idiopathic or other forms of autism. This study therefore investigated visual social attention in SYNGAP1-ID. Eye movements were recorded across three passive viewing tasks (face scanning, pop-out, and social preference) of differing social complexity in 24 individuals with SYNGAP1-ID and 12 typically developing controls. We found that SYNGAP1-ID participants looked at faces less than the controls, and when they did look at faces, they had less time looking at and fewer fixations to the eyes. For the pop-out task, where social and nonsocial objects (Phone, car, face, bird, and face-noise) were presented in an array, those with SYNGAP1-ID spent significantly less time looking at the phone stimulus as well as fewer fixations to the face compared with the typically developing controls. When looking at two naturalistic scenes side by side, one social in nature (e.g., with children present) and the other not, there were no differences between the SYNGAP1-ID group and typically developing controls on any of the examined eye tracking measures. This study provides novel findings on the social attention of those with SYNGAP1-ID and helps to provide further evidence for using eye tracking as an objective measure of the social phenotype in this population in future clinical trials.</p

    Profiling Autism and Attention Deficit Hyperactivity Disorder Traits in Children with SYNGAP1-Related Intellectual Disability

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    SYNGAP1-related ID is a genetic condition characterised by global developmental delay and epilepsy. Individuals with SYNGAP1-related ID also commonly show differences in attention and social communication/interaction and frequently receive additional diagnoses of Autism Spectrum Disorder (ASD) or Attention Deficit Hyperactivity Disorder (ADHD). We thus set out to quantify ASD and ADHD symptoms in children with this syndrome. To assess ASD and ADHD, parents and caregivers of a child with SYNGAP1-related ID (N = 34) or a typically developing control (N = 21) completed the Social Responsiveness Scale-2, the Social Communication Questionnaire with a subset of these also completing the Conners-3. We found that those with SYNGAP1-related ID demonstrated higher levels of autistic traits on both the SRS and SCQ than typically developing controls. On the SRS, those with SYNGAP1-related ID scored highest for restricted repetitive behaviours, and were least impaired in social awareness. On the Conners-3, those with SYNGAP1-related ID also showed a high prevalence of ADHD traits, with scores demonstrating difficulties with peer relations but relatively low occurrence of symptoms for DSM-5 conduct disorder and DSM-5 oppositional defiant disorder. Hierarchical clustering analysis highlighted distinct SYNGAP1-related ID subgroups for both ASD and ADHD traits. These findings provide further characterisation of the SYNGAP1-related ID behavioural phenotype, guiding diagnosis, assessment and potential interventions.</p
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