One objective of neuroscience is to understand a wide range of specific cognitive processes in terms of neuron activity. The huge amount of observational data about the brain makes achieving this objective challenging. Different models on different levels of detail provide some insight, but the relationship between models on different levels is not clear.
View Article and Find Full Text PDFVarious interpretations of the literature detailing the neural basis of learning have in part led to disagreements concerning how consciousness arises. Further, artificial learning model design has suffered in replicating intelligence as it occurs in the human brain. Here, we present a novel learning model, which we term the "Recommendation Architecture (RA) Model" from prior theoretical works proposed by Coward, using a dual-learning approach featuring both consequence feedback and non-consequence feedback.
View Article and Find Full Text PDFPacific Water (PW) enters the Arctic Ocean through Bering Strait and brings in heat, fresh water, and nutrients from the northern Bering Sea. The circulation of PW in the central Arctic Ocean is only partially understood due to the lack of observations. In this paper, pathways of PW are investigated using simulations with six state-of-the art regional and global Ocean General Circulation Models (OGCMs).
View Article and Find Full Text PDFOcean warming 'hotspots' are regions characterized by above-average temperature increases over recent years, for which there are significant consequences for both living marine resources and the societies that depend on them. As such, they represent early warning systems for understanding the impacts of marine climate change, and test-beds for developing adaptation options for coping with those impacts. Here, we examine five hotspots off the coasts of eastern Australia, South Africa, Madagascar, India and Brazil.
View Article and Find Full Text PDFTheoretical arguments demonstrate that practical considerations, including the needs to limit physiological resources and to learn without interference with prior learning, severely constrain the anatomical architecture of the brain. These arguments identify the hippocampal system as the change manager for the cortex, with the role of selecting the most appropriate locations for cortical receptive field changes at each point in time and driving those changes. This role results in the hippocampal system recording the identities of groups of cortical receptive fields that changed at the same time.
View Article and Find Full Text PDFGeophys Res Lett
February 2015
Unlabelled: Observational analyses of running 5 year ocean heat content trends () and net downward top of atmosphere radiation () are significantly correlated ( ∼ 0.6) from 1960 to 1999, but a spike in in the early 2000s is likely spurious since it is inconsistent with estimates of from both satellite observations and climate model simulations. Variations in between 1960 and 2000 were dominated by volcanic eruptions and are well simulated by the ensemble mean of coupled models from the Fifth Coupled Model Intercomparison Project (CMIP5).
View Article and Find Full Text PDFA model is described in which the hippocampal system functions as resource manager for the neocortex. This model is developed from an architectural concept for the brain as a whole within which the receptive fields of neocortical columns can gradually expand but with some limited exceptions tend not to contract. The definition process for receptive fields is constrained so that they overlap as little as possible, and change as little as possible, but at least a minimum number of columns detect their fields within every sensory input state.
View Article and Find Full Text PDFObjective: To evaluate a novel quantitative magnetic resonance (QMR) methodology (EchoMRI-AH, Echo Medical Systems) for measurement of whole-body fat and lean mass in humans.
Methods And Procedures: We have studied (i) the in vitro accuracy and precision by measuring 18 kg Canola oil with and without 9 kg water (ii) the accuracy and precision of measures of simulated fat mass changes in human subjects (n = 10) and (iii) QMR fat and lean mass measurements compared to those obtained using the established 4-compartment (4-C) model method (n = 30).
Results: (i) QMR represented 18 kg of oil at 40 degrees C as 17.
Background: Malnutrition in late infancy in developing countries may result from poor-quality complementary foods that displace breast milk.
Objective: The objective of the study was to assess the effects of fortified complementary blends of different energy densities on growth, hemoglobin concentrations, and breast milk intake of 9-mo-old Zambian infants.
Design: Infants were randomly assigned at 6 mo of age to receive for 3 mo a fortified blend of maize, beans, bambaranuts, and groundnuts [Chilenje Baby Mix (CBM); energy density: 68 kcal/100 g; n = 37] or a similar blend with alpha-amylase (CBMA; energy density: 106 kcal/100 g; n = 44).
There has been much discussion on what a scientific theory of consciousness would look like, and even whether such a theory is possible. Some common misunderstandings of the nature of theories (e.g.
View Article and Find Full Text PDFEnergy intake recommendations for infants are based on data from industrialized countries. FAO/WHO/UNU expressed the need for studies on total energy expenditure (TEE) and basal metabolic rate from developing countries covering current and changing lifestyles. For this observational study, 65 infants of differing socioeconomic status (SES) (n = 32 middle SES, n = 33 low SES) were selected in Pelotas, southern Brazil, aiming to: 1) compare TEE, minimum observable energy expenditure (MOEE), activity energy expenditure (AEE) between breast-fed infants 8.
View Article and Find Full Text PDFObjectives: We measured extraceLlular water (ECW) and intracellular water (ICW) volumes in peritoneal dialysis (PD) patients and controls to determine the effect of ICW variation on ECW/ICW ratio and to compare alternative ratios of ECW to height, height2, weight, and body surface area (BSA).
Patients And Methods: We measured body water compartments by deuterium oxide and bromide dilution in 29 PD patients (14 M, 15 F) and 31 controls (15 M, 16 F).
Results: ECW was similar in PD patients (17.
Although it is widely accepted that energy expenditure in infants is a function of feeding pattern, the mechanism behind this is not well understood. The objectives of this observational study were as follows: 1) to compare minimal observable energy expenditure (MOEE) between 2 subgroups of breast-fed infants, a BM group in which breast milk was the only source of milk and a BCM group given cow's milk in addition to breast milk; and 2) to identify potential mediators of a feeding pattern effect. For this purpose, infants were classified by feeding group on the basis of a mother's recall.
View Article and Find Full Text PDFBackground: Physical inactivity increases the risk of obesity, but the relations between reported levels of physical activity (PA) and measures of body fatness (BF) in children are remarkably inconsistent.
Objective: We examined the relation between objective measures of PA and body-composition indexes in nonobese children.
Design: A cross-sectional study was conducted in 100 children aged 6-8 y who were recruited according to their risk of future obesity: high-risk children had >/=1 obese parent [body mass index (BMI; in kg/m(2)): >30] and low-risk children had 2 nonobese biological parents (BMI: <30).
Background: Immunoglobulin A (IgA) in maternal milk may protect Gambian infants from early Helicobacter pylori colonization. This study sought evidence that this protection could be due to specific IgA antibodies.
Methods: Sixty-five infants were screened from 12 weeks of age with [13C]-urea breath tests.
Rapid Commun Mass Spectrom
July 2004
It has been proposed that the (13)C-octanoic acid breath test (OBT) provides a safe, non-radioactive means of measuring gastric emptying. However, deuterated octanoic acid provides a better marker when compared with scintigraphy, as the kinetics are less complex than those of the (13)C label. The appearance of (2)H in saliva is modelled as a two-compartment body water system, using an asymmetric triangular gastric emptying function.
View Article and Find Full Text PDFConscious Cogn
June 2004
In the physical sciences a rigorous theory is a hierarchy of descriptions in which causal relationships between many general types of entity at a phenomenological level can be derived from causal relationships between smaller numbers of simpler entities at more detailed levels. The hierarchy of descriptions resembles the modular hierarchy created in electronic systems in order to be able to modify a complex functionality without excessive side effects. Such a hierarchy would make it possible to establish a rigorous scientific theory of consciousness.
View Article and Find Full Text PDFObjectives: Body composition changes occur in peritoneal dialysis (PD) due to abnormalities in nutrition and hydration. We investigated abnormalities of nutrition and hydration in PD patients compared with healthy controls by measurement of total body potassium (TBK) and body water compartments.
Design: Cross-sectional comparison study.
Background: Colonization with Helicobacter pylori generally occurs in infancy, and the microorganism is often acquired from close family members. Rate of infant colonization may be affected by maternal immune status.
Methods: To investigate the potential protective effect of anti-H.
Background: Several formulae exist for estimating total body water (TBW). We aimed to assess their validity in peritoneal dialysis patients by comparison with TBW estimated by deuterium oxide dilution (TBW(D)).
Methods: We compared the equations of Chertow (TBW(Cher)), Chumlea (TBW(Chum)), Hume and Weyers (TBW(HW)), Johansson (TBW(J)), Lee (TBW(L)), Watson (TBW(W)) and TBW as 58% of body weight (TBW(0.
We have investigated a novel application of gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) for the quantitative analysis of the isoflavones in food matrices. Previous methods have been hampered by the lack of analytical standards to introduce early enough in the extraction procedure to allow compensations for losses at all stages of the procedure. In this work we have produced standard materials that can be added at the initial extraction, by intrinsically labelling soya plants by growing them in an atmosphere enriched in the stable isotope of carbon in CO(2).
View Article and Find Full Text PDFImportant aspects of glucose metabolism can be quantified by using the minimal model of glucose kinetics to interpret the results of intravenous glucose tolerance tests. The power of this methodology can be greatly increased by the addition of stable isotopically labelled tracer to the glucose bolus dose. This allows the separation of glucose disposal from endogenous glucose production and also increases the precision of the estimates of the physiological parameters measured.
View Article and Find Full Text PDFRapid Commun Mass Spectrom
February 2002
Gamma scintigraphy is considered the gold standard for the measurement of gastric emptying in humans. Recently, it has been proposed that a [(13)C]octanoate breath test can be used as an alternative technique for measuring gastric emptying of the solid phase, but the results from the two methods are not directly equivalent since in the breath test the label is subject to post-absorptive processing and consequently the emptying functions cannot be observed directly. This work investigates an alternative stable isotope method using deuterated octanoate where the kinetics of redistribution between and elimination from the various body pools are much more easily modelled.
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