The chemical compatibility of thermoplastic hose used in umbilicals

The effects of solvents and temperature on thermoplastic hose for umbilical service are reported in this paper. Accelerated ageing tests were undertaken and analysed by gravimetric, mechanical and calorimetric measurements. Water and methanol were found to cause physical degradation of the polymer, mainly at high temperatures, whereas xylene caused chemical degradation, which increased with increasing temperature. The activation energy for the alpha-process within polyethylene (PE) was found to be 96.3 kJ mol(-1) for un-aged PE and increased to 106.2 kJ moll after 64 days of ageing in water at 100degreesC. The changes in activation energy will be used to make a life-time prediction of umbilical line

Magnetocaloric effect in Gd/W thin film heterostructures

In an effort to understand the impact of nanostructuring on the magnetocaloric effect, we have grown and studied gadolinium in MgO/W(50 $\textrm{\AA}$)/[Gd(400 $\textrm{\AA}$)/W(50 $\textrm{\AA}$)]$_8$ heterostructures. The entropy change associated with the second order magnetic phase transition was determined from the isothermal magnetization for numerous temperatures and the appropriate Maxwell relation. The entropy change peaks at a temperature of 284 K with a value of approximately 3.4 J/kg-K for a 0-30 kOe field change; the full width at half max of the entropy change peak is about 70 K, which is significantly wider than that of bulk Gd under similar conditions. The relative cooling power of this nanoscale system is about 240 J/kg, somewhat lower than that of bulk Gd (410 J/kg). An iterative Kovel-Fisher method was used to determine the critical exponents governing the phase transition to be $\beta=0.51$, and $\gamma=1.75$. Along with a suppressed Curie temperature relative to the bulk, the fact that the convergent value of $\gamma$ is that predicted by the 2-D Ising model may suggest that finite size effects play an important role in this system. Together, these observations suggest that nanostructuring may be a promising route to tailoring the magnetocaloric response of materials

The Referral Process: Rural Primary Care Physicians\u27 Perspectives on Providing Counseling Referrals

The advantages to collaborative care between physicians and mental health care providers have been known for many decades. Rural primary care physicians (RPCPs) are the first professionals that most patients contact when they have a mental health concern, particularly in rural communities. It is therefore important to understand the process that occurs when a referral for counseling is made from a RPCP and the subsequent collaboration that occurs. The purpose of this qualitative study was to generate a model that provides a better understanding of the counseling referral process from the perspective of RPCPs in private practice in the Midwest. A grounded theory approach was used to analyze the data obtained through semi-structured interviews with twelve RPCPs and to construct a model that explains the process that RPCPs engage in when making counseling referrals. The Counseling Referral Evolution emerged from the interviews containing nine categories including: Perceived Mental Health Expertise of Physicians, Relationships with Mental Health Providers, Understanding of Counseling, Mental Health Complaint or Diagnosis, Referral Decisions, Method of Referral, Schedule Follow-up, Outcome, and Barriers. Additionally, the RPCPs suggested improvements for better collaboration between mental health practitioners and primary care physicians. Implications for mental health practitioners and primary care physicians are discussed

Frontostriatal Maturation Predicts Cognitive Control Failure to Appetitive Cues in Adolescents

Adolescent risk-taking is a public health issue that increases the odds of poor lifetime outcomes. One factor thought to influence adolescents' propensity for risk-taking is an enhanced sensitivity to appetitive cues, relative to an immature capacity to exert sufficient cognitive control. We tested this hypothesis by characterizing interactions among ventral striatal, dorsal striatal, and prefrontal cortical regions with varying appetitive load using fMRI scanning. Child, teen, and adult participants performed a go/no-go task with appetitive (happy faces) and neutral cues (calm faces). Impulse control to neutral cues showed linear improvement with age, whereas teens showed a nonlinear reduction in impulse control to appetitive cues. This performance decrement in teens was paralleled by enhanced activity in the ventral striatum. Prefrontal cortical recruitment correlated with overall accuracy and showed a linear response with age for no-go versus go trials. Connectivity analyses identified a ventral frontostriatal circuit including the inferior frontal gyrus and dorsal striatum during no-go versus go trials. Examining recruitment developmentally showed that teens had greater between-subject ventral-dorsal striatal coactivation relative to children and adults for happy no-go versus go trials. These findings implicate exaggerated ventral striatal representation of appetitive cues in adolescents relative to an intermediary cognitive control response. Connectivity and coactivity data suggest these systems communicate at the level of the dorsal striatum differentially across development. Biased responding in this system is one possible mechanism underlying heightened risk-taking during adolescence

Parental engagement on student academic self-efficacy and educational attainment expectation for immigrant youth.

With the increase of immigration to the United States, immigrant children have a unique position in the education system. Immigrant parents influence their children through different academic engagement practices. It is important to understand how parents impact students\u27 academic experiences. Employing the Educational Longitudinal Study of 2002, statistical analyses evaluated a sample of 2,514 high school sophomore immigrant students. The impact of parental engagement on the dependent variables were also compared between native language groups to learn whether or not specific cultural engagement practices impact student self-efficacy and attainment expectation differently. Findings revealed that parental engagement impacts academic self-efficacy and educational attainment expectation. Native language group differences indicated that the impact of parental engagement on the dependent variables was often greater for the Asian groups than Spanish and English speaking immigrants. Educators can use the information gained from this study to help immigrant parents improve their children\u27s academic experiences