Against the new Cartesian Circle

In two recent papers, Michael Della Rocca accuses Descartes of reasoning circularly in the Fourth Meditation. This alleged new circle is distinct from, and more vicious than, the traditional Cartesian Circle arising in the Third Meditation. We explain Della Rocca’s reasons for this accusation, showing that his argument is invalid

Disrupted GABAergic facilitation of working memory performance in people with schizophrenia.

ObjectivesGamma-Amiobutyric acid (GABA) is a primary inhibitory neurotransmitter that facilitates neural oscillations that coordinate neural activity between brain networks to facilitate cognition. The present magnetic resonance spectroscopy (MRS) study tests the hypothesis that GABAergic facilitation of working memory is disrupted in people with schizophrenia (PSZ).Methods51 healthy participants and 40 PSZ from the UC Davis Early Psychosis Program performed an item and temporal order working memory (WM) task and underwent resting MRS to measure GABA and glutamate concentrations in dorsolateral prefrontal (DLPFC) and anterior cingulate (ACC) regions of interest. MRS was acquired on a 3 Tesla Siemens scanner and GABA and glutamate concentrations were referenced to creatine. Percent correct on the WM task indexed performance and correlation coefficients examined GABAergic or Glutamatergic facilitation of WM, with Fisher's Z transformation testing for group differences.ResultsThere were no group differences in GABA or glutamate concentrations, but WM correlations were reversed between groups. In patients, higher DLPFC GABA was associated with worse rather than better WM performance. This pattern was not observed for glutamate or in the ACC. Although under-powered, there was no indication of medication effects.Conclusions and relevanceResults cannot be explained by group differences in DLPFC GABA or glutamate concentrations but, instead, indicate that schizophrenia disrupts the GABAergic facilitation of WM seen in healthy individuals. Results appear to parallel post mortem findings in suggesting that schizophrenia alters the distribution of different classes of GABAergic interneurons rather than producing a general deficit across the total population of neurons

Irrigating Corn on Well-Drained, Limestone-Derived Soils

In trying to determine if it would pay Kentucky farmers to irrigate corn, one of the most important steps is to ascertain the long-time average yield increases to be expected from supplemental irrigation. The yield data reported below are the results of an experiment applicable for a fairly large group of soils occurring in Kentucky

Impact of schizophrenia on anterior and posterior hippocampus during memory for complex scenes.

ObjectivesHippocampal dysfunction has been proposed as a mechanism for memory deficits in schizophrenia. Available evidence suggests that the anterior and posterior hippocampus could be differentially affected. Accordingly, we used fMRI to test the hypothesis that activity in posterior hippocampus is disproportionately reduced in schizophrenia, particularly during spatial memory retrieval.Methods26 healthy participants and 24 patients with schizophrenia from the UC Davis Early Psychosis Program were studied while fMRI was acquired on a 3 Tesla Siemens scanner. During encoding, participants were oriented to critical items through questions about item features (e.g., "Does the lamp have a square shade?") or spatial location (e.g., "Is the lamp on the table next to the couch?"). At test, participants determined whether scenes were changed or unchanged. fMRI analyses contrasted activation in a priori regions of interest (ROI) in anterior and posterior hippocampus during correct recognition of item changes and spatial changes.ResultsAs predicted, patients with schizophrenia exhibited reduced activation in the posterior hippocampus during detection of spatial changes but not during detection of item changes. Unexpectedly, patients exhibited increased activation of anterior hippocampus during detection of item changes. Whole brain analyses revealed reduced fronto-parietal and striatal activation in patients for spatial but not for item change trials.ConclusionsResults suggest a gradient of hippocampal dysfunction in which posterior hippocampus - which is necessary for processing fine-grained spatial relationships - is underactive, and anterior hippocampus - which may process context more globally - is overactive

Regional differences in the coupling between resting cerebral blood flow and metabolism may indicate action preparedness as a default state.

Although most functional neuroimaging studies examine task effects, interest intensifies in the "default" resting brain. Resting conditions show consistent regional activity, yet oxygen extraction fraction constancy across regions. We compared resting cerebral metabolic rates of glucose (CMRgl) measured with 18F-labeled 2-fluoro-2-deoxy-D-glucose to cerebral blood flow (CBF) 15O-H2O measures, using the same positron emission tomography scanner in 2 samples (n = 60 and 30) of healthy right-handed adults. Region to whole-brain ratios were calculated for 35 standard regions of interest, and compared between CBF and CMRgl to determine perfusion relative to metabolism. Primary visual and auditory areas showed coupling between CBF and CMRgl, limbic and subcortical regions--basal ganglia, thalamus and posterior fossa structures--were hyperperfused, whereas association cortices were hypoperfused. Hyperperfusion was higher in left than right hemisphere for most cortical and subcallosal limbic regions, but symmetric in cingulate, basal ganglia and somatomotor regions. Hyperperfused regions are perhaps those where activation is anticipated at short notice, whereas downstream cortical modulatory regions have longer "lead times" for deployment. The novel observation of systematic uncoupling of CBF and CMRgl may help elucidate the potential biological significance of the "default" resting state. Whether greater left hemispheric hyperperfusion reflects lateral dominance needs further examination

Fertilizing No-Till Corn

Results of an experiment conducted in 1968 at Princeton, Kentucky on low phosphate soil showed that surface-applied phosphorus was sufficiently available to no-till corn to produce good yields. This experiment was repeated again in the 1969 growing season with the results well in line with those reported for 1968 in Agronomy Research (Misc. 377) pages 41-43

Ebola Scare and Measles Resurgence: Mandatory Isolation/quarantine and Vaccination

Public outcry for radical isolation and quarantine policies followed the first Ebola diagnosis in the United States when Eric Duncan, upon his return home Oct 2014 from West Africa, then in the midst of a catastrophic Ebola epidemic, tested positive for Ebola. Likewise, the Dec 2014 Disneyland measles outbreak unleashed an angry backlash against parents who refused to have their children vaccinated; and there was public momentum to repeal all legal exemptions to mandatory vaccination of school children. This paper presents an ethical and legal analysis to adjudicate the issue which is at stake in both controversies; namely the inherent conflict between individual rights v. public health when the nation is threatened by serious communicable disease. It presents reasoned arguments, weighing duty-based v. consequence-maximizing ethical principles of right action through application of the felicity calculus (net utility). And the paper demonstrates how the metaethical theory of emotivism is operative in formation and expression of public sentiment which fueled the ethical and legal deliberations

Using Incongruent Equilibrium Hydration Reactions to Model Latter-Stage Crystallization in Plutons: Examples from the Bell Island Tonalite, Alaska

Models using hydration crystallization reactions (the reverse of dehydration melting reactions such as amph + qtz = px + melt) for the Bell Island pluton define incongruent equilibrium crystallization paths from hydrous + melt + pyroxene + Fe-Ti oxides + calcic andesine (30%-50% solid) to a solid tonalite consisting mostly of hornblende, lower temperature end of Bowen\u27s discontinuous reaction series and apply it to natural samples. Hydration crystallization provides an alternative to crystal fractionation for explaining variations in pluton chemistry, especially the compositions of late plutonic melts. Another characteristic of hydration crystallization is that the reactions have the potential to buffer the water content of the melt during crystallization. Two closed-system models, representing different sets of starting conditions and phases, are considered, based on least squares, mass-balance calculations of reactions and constrained by the petrography of the rocks. Model 1 starts with an average modified Bell Island leucotonalite melt coexisting with two pyroxenes, two Fe-Ti oxides, and plagioclase at the beginning of hydration crystallization. The starting assemblage of model 2 omits orthopyroxene and magnetite, includes amphibole, and uses a calculated melt composition. Both models generally predict, via different series of hydration crystallization reactions, the observed subsolidus mode. Model 2, however, is preferred based on petrographic observations of the Bell Island rocks, specifically the lack of magnetite and orthopyroxene, as well as certain textural features