Magnetic structure of Li2CuO2: From ab initio calculations to macroscopic simulations

The magnetic structure of the edge-sharing cuprate compound Li2CuO2 has been investigated with highly correlated ab initio electronic structure calculations. The first- and second-neighbor in-chain magnetic interactions are calculated to be 142 and -22 K, respectively. The ratio between the two parameters is smaller than suggested previously in the literature. The interchain interactions are antiferromagnetic in nature and of the order of a few K only. Monte Carlo simulations using the ab initio parameters to define the spin model Hamiltonian result in a Nel temperature in good agreement with experiment. Spin population analysis situates the magnetic moment on the copper and oxygen ions between the completely localized picture derived from experiment and the more delocalized picture based on local-density calculations.

Electronic and magnetic structure of LaMnO3 from hybrid periodic density-functional theory

The electronic and magnetic structures of the LaMnO3 compound have been studied by means of periodic calculations within the framework of spin polarized hybrid density-functional theory. In order to quantify the role of approximations to electronic exchange and correlation three different hybrid functionals have been used which mix nonlocal Fock and local Dirac-Slater exchange. Periodic Hartree-Fock results are also reported for comparative purposes. The A-antiferromagnetic ground state is properly predicted by all methods including Hartree-Fock exchange. In general, the different hybrid methods provide a rather accurate description of the band gap and of the two magnetic coupling constants, strongly suggesting that the corresponding description of the electronic structure is also accurate. An important conclusion emerging from this study is that the nature of the occupied states near the Fermi level is intermediate between the Hartree-Fock and local density approximation descriptions with a comparable participation of both Mn and O states.

Elder Abuse Task Force Report Pursuant to HF 2387: An Act Relating to Improvements to and Implementation of Laws Concerning Elder Abuse

During its 2012 session, Iowa’s 84th General Assembly passed House File 2387. The bill was signed into law by Governor Branstad and mandated a review of occurrences of and laws relating to abuse, neglect, or exploitation of individuals who are sixty years of age or older. After conducting the review, the twenty-three member Elder Abuse Task Force presents the following recommendations. These recommendations build upon current Iowa law and practice for the purpose of protecting older Iowans from abuse, neglect, and exploitation.

High-Temperature magnetic ordering in a new organic magnet

Magnetization, heat capacity, and neutron diffraction experiments on the beta-phase of the dithiadiazolyl radical, p-NC.C6F4.CNSSN., provide conclusive evidence that this system exhibits noncollinear antiferromagnetism at 35.5 K, an unprecedented temperature for an organic radical. On the basis of magnetization and powder neutron diffraction results, coupled with theoretical calculations of the spin distribution within the molecule, a magnetic structure for this compound is proposed in which the interactions propagate through S . . .N contacts.

Extent and limitations of density functional theory in describing magnetic systems

The performance of density-functional theory to solve the exact, nonrelativistic, many-electron problem for magnetic systems has been explored in a new implementation imposing space and spin symmetry constraints, as in ab initio wave function theory. Calculations on selected systems representative of organic diradicals, molecular magnets and antiferromagnetic solids carried out with and without these constraints lead to contradictory results, which provide numerical illustration on this usually obviated problem. It is concluded that the present exchange-correlation functionals provide reasonable numerical results although for the wrong physical reasons, thus evidencing the need for continued search for more accurate expressions.

Magnetic resonance imaging of Huntington's disease: preparing for clinical trials.

The known genetic mutation causing Huntington's disease (HD) makes this disease an important model to study links between gene and brain function. An autosomal dominant family history and the availability of a sensitive and specific genetic test allow pre-clinical diagnosis many years before the onset of any typical clinical signs. This review summarizes recent magnetic resonance imaging (MRI)-based findings in HD with a focus on the requirements if imaging is to be used in treatment trials. Despite its monogenetic cause, HD presents with a range of clinical manifestations, not explained by variation in the number of CAG repeats in the affected population. Neuroimaging studies have revealed a complex pattern of structural and functional changes affecting widespread cortical and subcortical regions far beyond the confines of the striatal degeneration that characterizes this disorder. Besides striatal dysfunction, functional imaging studies have reported a variable pattern of increased and decreased activation in cortical regions in both pre-clinical and clinically manifest HD-gene mutation carriers. Beyond regional brain activation changes, evidence from functional and diffusion-weighted MRI further suggests disrupted connectivity between corticocortical and corticostriatal areas. However, substantial inconsistencies with respect to structural and functional changes have been reported in a number of studies. Possible explanations include methodological factors and differences in study samples. There may also be biological explanations but these are poorly characterized and understood at present. Additional insights into this phenotypic variability derived from study of mouse models are presented to explore this phenomenon.

Iowa Sex Offender Treatment and Supervision Task Force Report to the Iowa General Assembly, January 15, 2007

Over the last several years, lawmakers have been responding to several highly publicized child abduction, assault and murder cases. While such cases remain rare in Iowa, the public debates they have generated are having far-reaching effects. Policy makers are responsible for controlling the nature of such effects. Challenges they face stem from the need to avoid primarily politically-motivated responses and the desire to make informed decisions that recognize both the strengths and the limitations of the criminal justice system as a vehicle for promoting safe and healthy families and communities. Consensus was reached by the Task Force at its first meeting that one of its standing goals is to provide nonpartisan guidance to help avoid or fix problematic sex offense policies and practices. Setting this goal was a response to the concern over what can result from elected officials’ efforts to respond to the types of sex offender-related concerns that can easily become emotionally laden and politically charged due to the universally held abhorrence of sex crimes against children. The meetings of the Task Force and the various work groups it has formed have included some spirited and perhaps emotionally charged discussions, despite the above-stated ground rule. However, as is described in the report, the Task Force’s first set of recommendations and plans for further study were approved through consensus. It is hoped that in upcoming legislative deliberations, it will be remembered that the non-legislative members of the Task Force all agreed on the recommendations contained in this report. The topics discussed in this first report from the Task Force are limited to the study issues specifically named in H.F. 619, the Task Force’s enabling legislation. However, other topics of concern were discussed by the Task Force because of their immediacy or because of their possible relationships with one or more of the Task Force’s mandated study issues. For example, it has been reported by some probation/parole officers and others that the 2000 feet rule has had a negative influence on treatment participation and supervision compliance. While such concerns were noted, the Task Force did not take it upon itself to investigate them at this time and thus broaden the agenda it was given by the General Assembly last session. As a result, the recently reinstated 2000 feet rule, the new cohabitation/child endangerment law and other issues of interest to Task Force members but not within the scope of their charge are not discussed in the body of this report. An issue of perhaps the greatest interest to most Task Force members that was not a part of their charge was a belief in the benefit of viewing Iowa’s efforts to protect children from sex crimes with as comprehensive a platform as possible. It has been suggested that much more can be done to prevent child-victim sex crimes than would be accomplished by only concentrating on what to do with offenders after a crime has occurred. To prevent child victimization, H.F. 619 policy provisions rely largely on incapacitation and future deterrent effects of increased penalties, more restrictive supervision practices and greater public awareness of the risk presented by a segment of Iowa’s known sex offenders. For some offenders, these policies will no doubt prevent future sex crimes against children, and the Task Force has begun long-term studies to look for the desired results and for ways to improve such results through better supervision tools and more effective offender treatment. Unfortunately, much of the effects from the new policies may primarily influence persons who have already committed sex offenses against minors and who have already been caught doing so. Task Force members discussed the need for a range of preventive efforts and a need to think about sex crimes against children from other than just a “reaction- to-the-offender” perspective. While this topic is not addressed in the report that follows, it was suggested that some of the Task Force’s discussions could be briefly shared through these opening comments. Along with incapacitation and deterrence, comprehensive approaches to the prevention of child-victim sex crimes would also involve making sure parents have the tools they need to detect signs of adults with sex behavior problems, to help teach their children about warning signs and to find the support they need for healthy parenting. School, faithbased and other community organizations might benefit from stronger supports and better tools they can use to more effectively promote positive youth development and the learning of respect for others, respect for boundaries and healthy relationships. All of us who have children, or who live in communities where there are children, need to understand the limitations of our justice system and the importance of our own ability to play a role in preventing sexual abuse and protecting children from sex offenders, which are often the child’s own family members. Over 1,000 incidences of child sexual abuse are confirmed or founded each year in Iowa, and most such acts take place in the child’s home or the residence of the caretaker of the child. Efforts to prevent child sexual abuse and to provide for early interventions with children and families at risk could be strategically examined and strengthened. The Sex Offender Treatment and Supervision Task Force was established to provide assistance to the General Assembly. It will respond to legislative direction for adjusting its future plans as laid out in this report. Its plans could be adjusted to broaden or narrow its scope or to assign different priority levels of effort to its current areas of study. Also, further Task Force considerations of the recommendations it has already submitted could be called for. In the meantime, it is hoped that the information and recommendations submitted through this report prove helpful.

Iowa Sex Offender Treatment and Supervision Task Force Report to the Iowa General Assembly, January 15, 2008

Over the last several years, lawmakers have been responding to several highly publicized child abduction, assault and murder cases. While such cases remain rare in Iowa, the public debates they have generated are having far-reaching effects. Policy makers are responsible for controlling the nature of such effects. Challenges they face stem from the need to avoid primarily politically-motivated responses and the desire to make informed decisions that recognize both the strengths and the limitations of the criminal justice system as a vehicle for promoting safe and healthy families and communities. Consensus was reached by the Task Force at its first meeting that one of its standing goals is to provide nonpartisan guidance to help avoid or fix problematic sex offense policies and practices. Setting this goal was a response to the concern over what can result from elected officials’ efforts to respond to the types of sex offender-related concerns that can easily become emotionally laden and politically charged due to the universally held abhorrence of sex crimes against children. The meetings of the Task Force and the various work groups it has formed have included some spirited and perhaps emotionally charged discussions, despite the above-stated ground rule. However, as is described in the report, the Task Force’s first set of recommendations and plans for further study were approved through consensus. It is hoped that in upcoming legislative deliberations, it will be remembered that the non-legislative members of the Task Force all agreed on the recommendations contained in this report. The topics discussed in this first report from the Task Force are limited to the study issues specifically named in H.F. 619, the Task Force’s enabling legislation. However, other topics of concern were discussed by the Task Force because of their immediacy or because of their possible relationships with one or more of the Task Force’s mandated study issues. For example, it has been reported by some probation/parole officers and others that the 2000 feet rule has had a negative influence on treatment participation and supervision compliance. While such concerns were noted, the Task Force did not take it upon itself to investigate them at this time and thus broaden the agenda it was given by the General Assembly last session. As a result, the recently reinstated 2000 feet rule, the new cohabitation/child endangerment law and other issues of interest to Task Force members but not within the scope of their charge are not discussed in the body of this report. An issue of perhaps the greatest interest to most Task Force members that was not a part of their charge was a belief in the benefit of viewing Iowa’s efforts to protect children from sex crimes with as comprehensive a platform as possible. It has been suggested that much more can be done to prevent child-victim sex crimes than would be accomplished by only concentrating on what to do with offenders after a crime has occurred. To prevent child victimization, H.F. 619 policy provisions rely largely on incapacitation and future deterrent effects of increased penalties, more restrictive supervision practices and greater public awareness of the risk presented by a segment of Iowa’s known sex offenders. For some offenders, these policies will no doubt prevent future sex crimes against children, and the Task Force has begun long-term studies to look for the desired results and for ways to improve such results through better supervision tools and more effective offender treatment. Unfortunately, much of the effects from the new policies may primarily influence persons who have already committed sex offenses against minors and who have already been caught doing so. Task Force members discussed the need for a range of preventive efforts and a need to think about sex crimes against children from other than just a “reaction- to-the-offender” perspective. While this topic is not addressed in the report that follows, it was suggested that some of the Task Force’s discussions could be briefly shared through these opening comments. Along with incapacitation and deterrence, comprehensive approaches to the prevention of child-victim sex crimes would also involve making sure parents have the tools they need to detect signs of adults with sex behavior problems, to help teach their children about warning signs and to find the support they need for healthy parenting. School, faithbased and other community organizations might benefit from stronger supports and better tools they can use to more effectively promote positive youth development and the learning of respect for others, respect for boundaries and healthy relationships. All of us who have children, or who live in communities where there are children, need to understand the limitations of our justice system and the importance of our own ability to play a role in preventing sexual abuse and protecting children from sex offenders, which are often the child’s own family members. Over 1,000 incidences of child sexual abuse are confirmed or founded each year in Iowa, and most such acts take place in the child’s home or the residence of the caretaker of the child. Efforts to prevent child sexual abuse and to provide for early interventions with children and families at risk could be strategically examined and strengthened. The Sex Offender Treatment and Supervision Task Force was established to provide assistance to the General Assembly. It will respond to legislative direction for adjusting its future plans as laid out in this report. Its plans could be adjusted to broaden or narrow its scope or to assign different priority levels of effort to its current areas of study. Also, further Task Force considerations of the recommendations it has already submitted could be called for. In the meantime, it is hoped that the information and recommendations submitted through this report prove helpful.