General anesthesia does not have persistent effects on attention in rodents

Background: Studies in animals have shown that general anesthesia can cause persistent spatial memory impairment, but the influence of anesthetics on other cognitive functions is unclear. This study tested whether exposure to general anesthesia without surgery caused a persistent deficit in attention in rodents.Methods: To evaluate whether anesthesia has persistent effects on attention, rats were randomized to three groups. Group A was exposed for 2 h to isoflurane anesthesia, and tested the following seven days for attentional deficits. Group B was used as a control and received room air before attentional testing. Since there is some evidence that a subanesthetic dose of ketamine can improve cognition and reduce disorders of attention after surgery, rats in group C were exposed to isoflurane anesthesia in combination with a ketamine injection before cognitive assessment. Attention was measured in rats using the 5-Choice Serial Reaction Time Task, for which animals were trained to respond with a nose poke on a touchscreen to a brief, unpredictable visual stimulus in one of five possible grid locations to receive a food reward. Attention was analyzed as % accuracy, % omission, and premature responses.Results: Evaluating acute attention by comparing baseline values with data from the day after intervention did not reveal any differences in attentional measurements. No significant differences were seen in % accuracy, % omission, and premature responses for the three groups tested for 7 consecutive days.Conclusion: These data in healthy rodents suggest that general anesthesia without surgery has no persistent effect on attention and the addition of ketamine does not alter the outcome

Medieval Iceland, Greenland, and the New Human Condition: A case study in integrated environmental humanities

This paper contributes to recent studies exploring the longue durée of human impacts on island landscapes, the impacts of climate and other environmental changes on human communities, and the interaction of human societies and their environments at different spatial and temporal scales. In particular, the paper addresses Iceland during the medieval period (with a secondary, comparative focus on Norse Greenland) and discusses episodes where environmental and climatic changes have appeared to cross key thresholds for agricultural productivity. The paper draws upon international, interdisciplinary research in the North Atlantic region led by the North Atlantic Biocultural Organization (NABO) and the Nordic Network for Interdisciplinary Environmental Studies (NIES) in the Circumpolar Networks program of the Integrated History and Future of People on Earth (IHOPE). By interlinking analyses of historically grounded literature with archaeological studies and environmental science, valuable new perspectives can emerge on how these past societies may have understood and coped with such impacts. As climate and other environmental changes do not operate in isolation, vulnerabilities created by socioeconomic factors also beg consideration. The paper illustrates the benefits of an integrated environmental-studies approach that draws on data, methodologies and analytical tools of environmental humanities, social sciences, and geosciences to better understand long-term human ecodynamics and changing human-landscape-environment interactions through time. One key goal is to apply previously unused data and concerted expertise to illuminate human responses to past changes; a secondary aim is to consider how lessons derived from these cases may be applicable to environmental threats and socioecological risks in the future, especially as understood in light of the New Human Condition, the concept transposed from Hannah Arendt's influential framing of the human condition that is foregrounded in the present special issue. This conception admits human agency's role in altering the conditions for life on earth, in large measure negatively, while acknowledging the potential of this self-same agency, if effectively harnessed and properly directed, to sustain essential planetary conditions through a salutary transformation of human perception, understanding and remedial action. The paper concludes that more long-term historical analyses of cultures and environments need to be undertaken at various scales. Past cases do not offer perfect analogues for the future, but they can contribute to a better understanding of how resilience and vulnerability occur, as well as how they may be compromised or mitigated

Hypoxia modulates cholinergic but not opioid activation of G proteins in rat hippocampus

Intermittent hypoxia, such as that associated with obstructive sleep apnea, can cause neuronal death and neurobehavioral dysfunction. The cellular and molecular mechanisms through which hypoxia alter hippocampal function are incompletely understood. This study used in vitro [ 35 S]guanylyl-5′- O -(Γ-thio)-triphosphate ([ 35 S]GTPΓS) autoradiography to test the hypothesis that carbachol and DAMGO activate hippocampal G proteins. In addition, this study tested the hypothesis that in vivo exposure to different oxygen (O 2 ) concentrations causes a differential activation of G proteins in the CA1, CA3, and dentate gyrus (DG) regions of the hippocampus. G protein activation was quantified as nCi/g tissue in CA1, CA3, and DG from rats housed for 14 days under one of three different oxygen conditions: normoxic (21% O 2 ) room air, or hypoxia (10% O 2 ) that was intermittent or sustained. Across all regions of the hippocampus, activation of G proteins by the cholinergic agonist carbachol and the mu opioid agonist [D-Ala 2 , N-Met-Phe 4 , Gly 5 ] enkephalin (DAMGO) was ordered by the degree of hypoxia such that sustained hypoxia > intermittent hypoxia > room air. Carbachol increased G protein activation during sustained hypoxia (38%), intermittent hypoxia (29%), and room air (27%). DAMGO also activated G proteins during sustained hypoxia (52%), intermittent hypoxia (48%), and room air (43%). Region-specific comparisons of G protein activation revealed that the DG showed significantly less activation by carbachol following intermittent hypoxia and sustained hypoxia than the CA1. Considered together, the results suggest the potential for hypoxia to alter hippocampal function by blunting the cholinergic activation of G proteins within the DG. © 2007 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/57386/1/20312_ftp.pd

Climate challenges, vulnerabilities, and food security

This paper identifies rare climate challenges in the long-term history of seven areas, three in the subpolar North Atlantic Islands and four in the arid-to-semiarid deserts of the US Southwest. For each case, the vulnerability to food shortage before the climate challenge is quantified based on eight variables encompassing both environmental and social domains. These data are used to evaluate the relationship between the “weight” of vulnerability before a climate challenge and the nature of social change and food security following a challenge. The outcome of this work is directly applicable to debates about disaster management policy

Structure and spatial pattern of vegetation in a caatinga area

A vegetação do Nordeste revela carência relacionada ao manejo florestal da Caatinga. Objetivou-se estudar o padrão espacial de espécies e estrutura da vegetação em área de Caatinga, localizada no município de Floresta, PE. Em uma área de aproximadamente 10 ha, com histórico de perturbação, foram instaladas 20 parcelas de 20 x 20 m, de forma sistemática. Todas as árvores com CAP a 1,30 m do solo ≥ 6 cm foram identificadas e tiveram suas circunferências e alturas mensuradas. Foram encontradas 18 espécies arbóreas, distribuídas em 15 gêneros, dentro de 6 famílias botânicas, com índice de diversidade de Shannon (H') de 2,11 nats.ind-1, e área basal total estimada de 4,53 m2.ha-1. Destacaram-se as famílias Fabaceae, com 48,93% dos indivíduos, e Euphorbiaceae, com 41,28%. As espécies Poincianella bracteosa (Tul.) L. P. Queiroz, Croton rhamnifolius Kunth, Manihot cartaginenses subsp. glaziovii (Muell. Arg.) Allem. e Mimosa ophtalmocentra Mart. ex Benth somaram 55% do total do valor de importância. A maioria das espécies apresentou distribuição agregada, exceto algumas, como Myracrodruon urundeuva Fr. Allem. para o índice de McGuinnes (IGA), Commiphora leptophloeos (Mart.) J. B. Gillett para McGuinnes (IGA) e Payandeh (Pi) e Manihot cartaginenses subsp. glaziovii (Muell. Arg.) Allem. para Fracker e Brischle (Ki), que obtiveram tendência ao agrupamento.Palavras-chave: Semiárido; Pernambuco; distribuição espacial.AbstractStructure and spatial pattern of vegetation in a caatinga area. Forest management deficiency in relation to Northeast vegetation, specifically caatinga, are remarkable. This research aims to analyze spatial patterns of species and vegetation structure in Caatinga area, located in the municipality of Floresta-PE. In an area of approximately 10 ha, and a history of disturbance, 20 plots (20 x 20 m) were installed in systematic way. All trees with CAP (at 1.30 m above the ground) ≥ 6 cm had been identified, and their circumferences and heights measured. 18 tree species were sampled, distributed in 15 genus, within 6 botanical families, with diversity index of Shannon (H ') of 2.11 nats / ind, and estimated total basal area of 4, 53 m2.ha-1. The highlighted families were Fabaceae, 48.93% of individuals, and Euphorbiaceae 41.28%. The species Poincianella bracteosa (Tul.) L.P.Queiroz, Croton rhamnifolius Kunth, Manihot cartaginenses Subsp. glaziovii (Muell. Arg.) Allem., and Mimosa ophtalmocentra Mart. ex Benth totalized 55% of the total value of importance. Most species revealed aggregated distribution, except some like Myracrodruon urundeuva Fr. Allem. for the McGuinness index (IGA), Commiphora leptophloeos (Mart.) J.B.Gillett for McGuinness (IGA) and Payandeh (Pi), and Manihot cartaginenses Subsp. glaziovii (Muell. Arg.) Allem. for Fracker and Brischle (Ki), which obtained grouping tendency.Keywords: Semiarid; Pernambuco; spatial distribution. AbstractForest management deficiency in relation to Northeast vegetation, specifically caatinga, are remarkable. This research aims to analyze spatial patterns of species and vegetation structure in Caatinga area, located in the municipality of Floresta-PE. In an area of approximately 10 ha, and a history of disturbance, 20 plots (20 x 20 m) were installed in systematic way. All trees with CAP (at 1.30 m above the ground) ≥ 6 cm had been identified, and their circumferences and heights measured. 18 tree species were sampled, distributed in 15 genus, within 6 botanical families, with diversity index of Shannon (H ') of 2.11 nats / ind, and estimated total basal area of 4, 53 m2.ha-1. The highlighted families were Fabaceae, 48.93% of individuals, and Euphorbiaceae 41.28%. The species Poincianella bracteosa (Tul.) L.P.Queiroz, Croton rhamnifolius Kunth, Manihot cartaginenses Subsp. glaziovii (Muell. Arg.) Allem., and Mimosa ophtalmocentra Mart. ex Benth totalized 55% of the total value of importance. Most species revealed aggregated distribution, except some like Myracrodruon urundeuva Fr. Allem. for the McGuinness index (IGA), Commiphora leptophloeos (Mart.) J.B.Gillett for McGuinness (IGA) and Payandeh (Pi), and Manihot cartaginenses Subsp. glaziovii (Muell. Arg.) Allem. for Fracker and Brischle (Ki), which obtained grouping tendency.Keywords: Semiarid; Pernambuco; spatial distribution

Communications Biophysics

Contains reports on five research projects.National Science Foundation (Grant G-16526)National Institutes of Health (Grant MH-04737-02

Heart failure patients demonstrate impaired changes in brachial artery blood flow and shear rate pattern during moderate-intensity cycle exercise

New Findings What is the central question of this study? We explored whether heart failure (HF) patients demonstrate different exercise-induced brachial artery shear rate patterns compared with control subjects. What is the main finding and its importance? Moderate-intensity cycle exercise in HF patients is associated with an attenuated increase in brachial artery anterograde and mean shear rate and skin temperature. Differences between HF patients and control subjects cannot be explained fully by differences in workload. HF patients demonstrate a less favourable shear rate pattern during cycle exercise compared with control subjects. Repeated elevations in shear rate (SR) in conduit arteries, which occur during exercise, represent a key stimulus to improve vascular function. We explored whether heart failure (HF) patients demonstrate distinct changes in SR in response to moderate-intensity cycle exercise compared with healthy control subjects. We examined brachial artery SR during 40 min of cycle exercise at a work rate equivalent to 65% peak oxygen uptake in 14 HF patients (65 ± 7 years old, 13 men and one woman) and 14 control subjects (61 ± 5 years old, 12 men and two women). Brachial artery diameter, SR and oscillatory shear index (OSI) were assessed using ultrasound at baseline and during exercise. The HF patients demonstrated an attenuated increase in mean and anterograde brachial artery SR during exercise compared with control subjects (time × group interaction, P = 0.003 and P 0.05). In conclusion, HF patients demonstrate a less favourable SR pattern during cycle exercise than control subjects, characterized by an attenuated mean and anterograde SR and by increased OSI

Help-seeking pathways in early psychosis

INTRODUCTION: Understanding the help-seeking pathways of patients with a putative risk of developing psychosis helps improving development of specialised care services. This study aimed at obtaining information about: type of health professionals contacted by patients at putative risk for psychosis on their help-seeking pathways; number of contacts; type of symptoms leading to contacts with health professionals; interval between initial contact and referral to a specialised outpatient service. METHOD: The help-seeking pathways were assessed as part of a prospective study in 104 patients with suspected at-risk states for psychosis. RESULTS: The mean number of contacts prior to referral was 2.38. Patients with psychotic symptoms more often contacted mental health professionals, whereas patients with insidious and more unspecific features more frequently contacted general practitioners (GPs). CONCLUSIONS: GPs have been found to under-identify the insidious features of emerging psychosis (Simon et al. (2005) Br J Psychiatry 187:274–281). The fact that they were most often contacted by patients with exactly these features calls for focussed and specialised help for primary care physicians. Thus, delays along the help-seeking pathways may be shortened. This may be of particular relevance for patients with the deficit syndrome of schizophrenia

Direct observation of Anderson localization of matter-waves in a controlled disorder

We report the observation of exponential localization of a Bose-Einstein condensate (BEC) released into a one-dimensional waveguide in the presence of a controlled disorder created by laser speckle . We operate in a regime allowing AL: i) weak disorder such that localization results from many quantum reflections of small amplitude; ii) atomic density small enough that interactions are negligible. We image directly the atomic density profiles vs time, and find that weak disorder can lead to the stopping of the expansion and to the formation of a stationary exponentially localized wave function, a direct signature of AL. Fitting the exponential wings, we extract the localization length, and compare it to theoretical calculations. Moreover we show that, in our one-dimensional speckle potentials whose noise spectrum has a high spatial frequency cut-off, exponential localization occurs only when the de Broglie wavelengths of the atoms in the expanding BEC are larger than an effective mobility edge corresponding to that cut-off. In the opposite case, we find that the density profiles decay algebraically, as predicted in [Phys. Rev. Lett. 98, 210401 (2007)]. The method presented here can be extended to localization of atomic quantum gases in higher dimensions, and with controlled interactions