bluuebunny/crossref_metadata_2025 huggingface dataset:
Brain Activation during Anticipation of Sound Sequences
Authors: Leaver Amber M. , Van Lare Jennifer , Zielinski Brandon , Halpern Andrea R. , Rauschecker Josef P.
Published: February 2009

Music consists of sound sequences that require integration over time. As we become familiar with music, associations between notes, melodies, and entire symphonic movements become stronger and more complex. These associations can become so tight that, for example, hearing the end of one album track can elicit a robust image of the upcoming track while anticipating it in total silence. Here, we study this predictive “anticipatory imagery” at various stages throughout learning and investigate activity changes in corresponding neural structures using functional magnetic resonance imaging. Anticipatory imagery (in silence) for highly familiar naturalistic music was accompanied by pronounced activity in rostral prefrontal cortex (PFC) and premotor areas. Examining changes in the neural bases of anticipatory imagery during two stages of learning conditional associations between simple melodies, however, demonstrates the importance of fronto-striatal connections, consistent with a role of the basal ganglia in “training” frontal cortex (Pasupathy and Miller, 2005). Another striking change in neural resources during learning was a shift between caudal PFC earlier to rostral PFC later in learning. Our findings regarding musical anticipation and sound sequence learning are highly compatible with studies of motor sequence learning, suggesting common predictive mechanisms in both domains.
The BOLD Response in the Rat Hippocampus Depends Rather on Local Processing of Signals than on the Input or Output Activity. A Combined Functional MRI and Electrophysiological Study
Authors: Angenstein Frank , Kammerer Elena , Scheich Henning
Published: February 2009

Functional magnetic resonance imaging (fMRI) of the human brain is widely used in neuroscience, but the exact relationship between measured fMRI response and the underlying changes in neuronal activity is still elusive. To obtain further information about the specific roles of synaptic (input) and spiking activity (output) for the generation of fMRI-related signals, we used an approach that combines electrophysiological and MRI measurements in the anatomically and physiologically well defined rat hippocampus. Direct electrical stimulation of the perforant pathway enabled us to control synchronized input activity to the dentate gyrus, whereas recorded population spikes from the granular cell layer indicated the dentate output activity. The perforant pathway was first stimulated with 15 identical pulse trains (10 Hz for 8 s), and evoked blood oxygenation level-dependent (BOLD) responses and population spikes were measured for each individual stimulus train. Spatial and magnitude aspects of the elicited BOLD responses differentially changed in the dentate gyrus and hippocampus from early to late stimulus trains together with population spike latencies in the dentate indicating delayed inhibitory network processing. Furthermore, the same number of stimuli presented in different patterns within trains (i.e., bursts of 10 stimuli at 50, 100, or 200 Hz) clearly altered the BOLD responses. Similarly, variations in the BOLD response also occurred when different stimulus patterns were chosen that caused the same number of population spikes. The results indicate that neuronal network activity including inhibitory interneurons rather than exclusively the input or spiking activity of the principal neurons determine a BOLD response to repetitive stimuli.
Augmented Hippocampal Ripple Oscillations in Mice with Reduced Fast Excitation onto Parvalbumin-Positive Cells
Authors: Rácz Attila , Ponomarenko Alexey A. , Fuchs Elke C. , Monyer Hannah
Published: February 2009

Generation of fast network oscillations in the hippocampus relies on interneurons, but the underlying specific synaptic mechanisms are not established. The excitatory recruitment of fast-spiking interneurons during hippocampal sharp waves has been suggested to be critical for the generation of 140–200 Hz (“ripple”) oscillations in the CA1 area. To directly test this, we used genetically modified mice (PV–ΔGluR-A) with reduced AMPA receptor-mediated excitation onto parvalbumin (PV)-positive interneurons and studied hippocampal oscillations in freely moving animals. In PV–ΔGluR-A mice, ripple-amplitude and associated rhythmic modulation of pyramidal cells and fast-spiking interneurons were increased. These changes were not accompanied by concurrent alterations of firing rates. Neither theta nor gamma oscillations displayed marked alterations in the mutant. These results provide evidence that fast excitation from pyramidal cells to PV-positive interneurons differentially influences ripple and gamma oscillationsin vivo.
Wide-Dynamic-Range Forward Suppression in Marmoset Inferior Colliculus Neurons Is Generated Centrally and Accounts for Perceptual Masking
Authors: Nelson Paul C. , Smith Zachary M. , Young Eric D.
Published: February 2009

An organism's ability to detect and discriminate sensory inputs depends on the recent stimulus history. For example, perceptual detection thresholds for a brief tone can be elevated by as much as 50 dB when following a masking stimulus. Previous work suggests that such forward masking is not a direct result of peripheral neural adaptation; the central pathway apparently modifies the representation in a way that further attenuates the input's response to short probe signals. Here, we show that much of this transformation is complete by the level of the inferior colliculus (IC). Single-neuron extracellular responses were recorded in the central nucleus of the awake marmoset IC. The threshold for a 20 ms probe tone presented at best frequency was determined for various masker-probe delays, over a range of masker sound pressure levels (SPLs) and frequencies. The most striking aspect of the data was the increased potency of forward maskers as their SPL was increased, despite the fact that the excitatory response to the masker was often saturating or nonmonotonic over the same range of levels. This led to probe thresholds at high masker levels that were almost always higher than those observed in the auditory nerve. Probe threshold shifts were not usually caused by a persistent excitatory response to the masker; instead we propose a wide-dynamic-range inhibitory mechanism locked to sound offset as an explanation for several key aspects of the data. These findings further delineate the role of subcortical auditory processing in the generation of a context-dependent representation of ongoing acoustic scenes.
D1-Receptor Impact on Neuroplasticity in Humans
Authors: Nitsche Michael A. , Kuo Min-Fang , Grosch Jan , Bergner Christin , Monte-Silva Katia , Paulus Walter
Published: February 2009

Dopamine improves learning and memory formation. The neurophysiological basis for these effects might be a focusing effect of dopamine on neuroplasticity: Accordingly, in humansl-dopa prolongs focal facilitatory plasticity, but turns nonfocal facilitatory plasticity into inhibition. Here we explore the impact of D1receptors on plasticity. Nonfocal plasticity was induced by transcranial direct current stimulation (tDCS), and focal plasticity by paired associative stimulation (PAS). Subjects received sulpiride, a D2antagonist, to increase the relative contribution of D1receptors to dopaminergic activity, combined sulpiride andl-dopa, to increase the relation of D1/D2activity further, or placebo medication. Under placebo, anodal tDCS and excitatory PAS (ePAS) increased motor cortex excitability. Cathodal tDCS and inhibitory PAS (iPAS) reduced it. Sulpiride abolished iPAS-induced inhibition, but not ePAS-generated facilitation, underlining the importance of D1-receptor activity for focal facilitatory neuroplasticity. Combining sulpiride withl-dopa reestablished iPAS-induced inhibition, but did not affect ePAS-induced plasticity. tDCS-induced plasticity, which was abolished by sulpiride in a former study, also recovered. Thus enhancing D1activity further relative to D2activity is relevant for facilitatory and inhibitory plasticity. However, comparison with former results show that an appropriate balance of D1and D2activity seems necessary to (1) consolidate the respective excitability modifications and (2) to elicit a focusing effect.
The Neuropeptide Pigment-Dispersing Factor Adjusts Period and Phase ofDrosophila's Clock
Authors: Yoshii Taishi , Wülbeck Corinna , Sehadova Hana , Veleri Shobi , Bichler Dominik , Stanewsky Ralf , Helfrich-Förster Charlotte
Published: February 2009

The neuropeptide pigment-dispersing factor (PDF) is a key transmitter in the circadian clock ofDrosophila melanogaster.PDF is necessary for robust activity rhythms and is thought to couple the circadian oscillations of the clock neurons. However, little is known about the action of PDF on individual clock neurons. Here, we combined theperiod–luciferase reporter system with immunolabeling of clock proteins in wild-type andPdf01mutants to dissect the effects of PDF on specific subgroups of clock neurons. Additionally, PDF levels were elevated to higher than normal levels using specific neural mutants, and a correlation analysis of locomotor activity and clock protein staining served to determine the periods of specific clock cells. We found that PDF has multiple effects on the clock neurons: In some groups of clock neurons, PDF was required for maintaining the oscillations of individual cells, and in others, PDF was required for synchronous cycling of the individual members. Other clock neurons cycled with high amplitude in absence of PDF, but PDF affected their intrinsic clock speed. Sometimes PDF shortened and sometimes PDF lengthened period. Our observations indicate that PDF is crucial for adjusting cycling amplitude, period, and phase of the different players in the circadian clock. Under natural conditions PDF may be required for adaptingDrosophila's clock to varying photoperiods. Indeed, we show here thatPdf01mutants are not able to adapt their activity to long photoperiods in a wild-type manner.
Age-Dependent Alterations of Corticostriatal Activity in the YAC128 Mouse Model of Huntington Disease
Authors: Joshi Prasad R. , Wu Nan-Ping , André Véronique M. , Cummings Damian M. , Cepeda Carlos , Joyce John A. , Carroll Jeffrey B. , Leavitt Blair R. , Hayden Michael R. , Levine Michael S. , Bamford Nigel S.
Published: February 2009

Huntington disease is a genetic neurodegenerative disorder that produces motor, neuropsychiatric, and cognitive deficits and is caused by an abnormal expansion of the CAG tract in the huntingtin (htt) gene. In humans, mutated htt induces a preferential loss of medium spiny neurons in the striatum and, to a lesser extent, a loss of cortical neurons as the disease progresses. The mechanisms causing these degenerative changes remain unclear, but they may involve synaptic dysregulation. We examined the activity of the corticostriatal pathway using a combination of electrophysiological and optical imaging approaches in brain slices and acutely dissociated neurons from the YAC128 mouse model of Huntington disease. The results demonstrated biphasic age-dependent changes in corticostriatal function. At 1 month, before the behavioral phenotype develops, synaptic currents and glutamate release were increased. At 7 and 12 months, after the development of the behavioral phenotype, evoked synaptic currents were reduced. Glutamate release was decreased by 7 months and was markedly reduced by 12 months. These age-dependent alterations in corticostriatal activity were paralleled by a decrease in dopamine D2receptor modulation of the presynaptic terminal. Together, these findings point to dynamic alterations at the corticostriatal pathway and emphasize that therapies directed toward preventing or alleviating symptoms need to be specifically designed depending on the stage of disease progression.
Monkey Orbitofrontal Cortex Encodes Response Choices Near Feedback Time
Authors: Tsujimoto Satoshi , Genovesio Aldo , Wise Steven P.
Published: February 2009

The primate prefrontal cortex contributes to stimulus-guided behavior, but the functional specializations among its areas remain uncertain. To better understand such specializations, we contrasted neuronal activity in the dorsolateral prefrontal cortex (PFdl) and the orbital prefrontal cortex (PFo). The task required rhesus monkeys to use a visual cue to choose a saccade target. Some cues instructed the monkeys to repeat their most recent response; others instructed them to change it. Responses were followed by feedback: fluid reward if correct, visual feedback if incorrect. Previous studies, using different tasks, have reported that PFo neurons did not encode responses. We found PFo did encode responses in this task, but only near feedback time, after the response had been completed. PFdl differed from PFo in several respects. As reported previously, some PFdl neurons encoded responses from the previous trial and others encoded planned responses. PFo neurons did not have these properties. After feedback, PFdl encoded rewarded responses better than unrewarded ones and thus combined response and outcome information. PFo, in contrast, encoded the responses chosen, rewarded or not. These findings suggest that PFdl and PFo contribute differently to response knowledge, with PFo using an outcome-independent signal to monitor current responses at feedback time.
Democratizing States and the Use of History*
Authors: Gilbert Jess
Published: February 2009

Abstract  A pervasive anti‐statism often blinds us to the democratic victories in the past and thus to possibilities in our future. This article argues that big government can democratize society and uses historical investigation to make the point. The study of history emancipates us from the tyranny of the present. Progressive social change has come about in the United States and elsewhere as combined bottom‐up, top‐down initiatives. I present two such cases of democratization during the New Deal era. The first is about rural sociologists' participatory‐action research with local citizens for policy planning. This program, while short‐lived, fed into the creation of the field of community development. The other is a land‐reform experiment among poor African Americans. In the 1960s these “resettlement communities” became local strongholds of the civil‐rights movement, and their descendants carry on the struggle today. I use these two historical instances to show that big states as well as social scientists have been effective agents of democracy, and suggest that they can be again. History then enable us to re‐imagine, re‐new, and re‐form our democratic tradition of rural sociology.
The Social Basis of Agro‐Environmental Concern: Physical versus Social Proximity
Authors: Sharp Jeff , Adua Lazarus
Published: February 2009

Abstract In this study, we explore the social basis of environmental concern, specifically focusing on attitudes about the agricultural environment in relation to an individual's geographic and social distance from agriculture. We also consider the significance of rural recreational behaviors in relation to agro‐environmental concern. The analysis, based on data from a statewide survey of Ohioans, reveals a strong relationship between one's geographic location along the rural‐urban continuum and attitudes about agriculture and the environment. This relationship, though, does not exist once the effects of social proximity to agriculture are accounted for, suggesting that the relationship between residential location along the rural‐urban continuum and agro‐environmental attitudes may be spurious. The analysis also reveals a strong relationship between participation in rural recreation and attitudes about agriculture and the environment. We describe several conceptual and practical implications of this research for natural‐resource management.
Changes in epidemiology, etiology, diagnostics, and therapy of acute appendicitis
Authors: Antal András
Published: February 2009

The frequency of acute appendicitis has fallen in the last three decades in developed industrialized countries. From 1961 to 1991 the number of appendectomies performed annually in Hungary decreased significantly. Since 1991 the numbers are essentially unchanged. Appendix lumen obstruction was formerly believed to be crucial in the etiology of the illness, while today mixed aerobic, anaerobic bacterial infection is considered more important. The inflammation process – according to immunogenetic differences – may lead to recovery or tissue necrosis and perforation. To date, no methods are known that could timely distinguish spontaneously healing or conservatively treatable appendicitis from those resulting in tissue necrosis, although routine usage of abdominal ultrasound technique is added to the clinical picture’s modern diagnostic arsenal. The operation method for removing the appendix also changed. Experiences confirmed that laparoscopic appendectomy is usually more favorable in the treatment of acute appendicitis than traditional surgery.
Diel Movement Patterns of Yellow Perch in a Simple and a Complex Lake Basin
Authors: Bauer William F. , Radabaugh Nicholas B. , Brown Michael L.
Published: February 2009

To investigate the influence habitat may have on fish movement, we tagged two length-groups of adult yellow perch Perca flavescens with ultrasonic transmitters to determine diel movement patterns in two glacial lakes with differing basin morphometries and habitat characteristics. In both lakes, movement rates increased from dawn to the diurnal period, and decreased from dusk to the nocturnal period, with lowest activity in the nocturnal period. Overall, mean period movement rates for yellow perch were higher in the simple lake than in the complex lake. Offshore movement from the nocturnal to the dawn period and onshore movement from the diurnal to the nocturnal period was evident in both length-groups in the complex lake, but not evident in the simple lake. Size segregation was apparent in the complex lake, where the small length-group was located farther from shore than the large length-group. Yellow perch in the simple lake most often used the deepest depths, whereas yellow perch in the complex lake used moderate depths. These results suggest that habitat characteristics and the complexity of a lake basin may have an influence on behavior and habitat use. With this insight into the movement patterns of yellow perch in two distinct types of lake basins, managers may consider refining sampling plans for individual lake types.
Habitat Characteristics of Black Crappie Nest Sites in an Illinois Impoundment
Authors: Phelps Quinton E. , Lohmeyer Adam M. , Wahl Nicholas C. , Zeigler John M. , Whitledge Gregory W.
Published: February 2009

Ten nest colonies of black crappie Pomoxis nigromaculatus were visually located and verified by angling in Campus Lake, a small urban impoundment in southern Illinois. Habitat characteristics were measured at these nest sites and compared to habitat measurements obtained from 45 unused sites. Seven habitat characteristics (substrate firmness, temperature, dissolved oxygen, distance to deep water [3.8-m depth contour], substrate type, vegetation height, and vegetation density) were significantly different between nest sites and unused sites. Although temperature and dissolved oxygen were significantly different between nest sites and unused sites, all values were within the suitable range for black crappie spawning to occur. Black crappies selected nest sites close to deep water with firm substrates and low vegetation height and density. Our results present insight on habitat characteristics of black crappie spawning locations in a small urban impoundment. Interestingly, we located several black crappie nesting colonies with more than 10 individual nests in close proximity to one another; colonial nesting by black crappies has not previously been reported in the literature. Furthermore, we suggest that degree of shoreline modification and other anthropogenic influences in and adjacent to Campus Lake did not affect black crappie nest site selection. Black crappie nest sites in Campus Lake were always located near deep water (3.8 m), in low-density, short vegetation, and on firm clay or sand substrate; because nest site selection can influence earlylife survival and recruitment of black crappie, the availability of these habitat characteristics may regulate black crappie population demographics in Campus Lake. Efforts to limit sediment inputs will be important for maintaining suitable black crappie spawning habitat in Campus Lake and other small impoundments.
Developing Model-Based Indices of Lake Whitefish Abundance Using Commercial Fishery Catch and Effort Data in Lakes Huron, Michigan, and Superior
Authors: Deroba Jonathan J. , Bence James R.
Published: February 2009

Fishery catch per effort (CPE) is often used to assess relative fish abundance, and in many Great Lakes and other freshwater applications the CPE index is based on either an average or the ratio of summed aggregate catch to summed aggregate effort. In particular, assessments used to estimate the abundance of lake whitefish Coregonus clupeaformis and recommend harvest quotas in 1836 Treaty-ceded waters of Lakes Huron, Michigan, and Superior assume that commercial CPE from gill-net and trap-net fisheries is proportional to abundance; however, CPE may change due to factors other than abundance, leading to violations of this assumption. To account for sources of CPE variation that are not attributable to abundance, general linear mixed models (GLMMs) were developed for each management unit and least-squares means (LSMs) for each year were used as the index of abundance. The effect of using the GLMM method for standardization was evaluated by examining the temporal trends in the proportional difference between LSMs and CPE (i.e., aggregate catch divided by aggregate effort for each year). Of the random effects included in the final GLMM for the gill-net fishery, license holder accounted for the most variation. The fixed effect of boat size category on CPE depended on lake; on average, there was little difference between boat sizes in Lake Superior, whereas large boats had a lower CPE than medium and small boats in Lakes Michigan and Huron. On average, CPE was higher from October to December than during other months. The proportional difference between LSMs and CPE trended through time in some management units, suggesting the importance of adjusting fishery CPE for effects like boat size, season, and license holder. Factors that influence lake whitefish commercial fishery CPE are similar to factors important for marine commercial fisheries.
At Loggerheads: Gear Damage in the Blue Crab Fishery Attributed to Loggerhead Sea Turtles
Authors: Avissar Naomi , Hart Kristen M. , Crowder Larry B. , Gannon Janet , Marsh Jesse C.
Published: February 2009

North Carolina's fishery for the blue crab Callinectes sapidus is experiencing problems with gear damage during the summer season. Individuals of a protected species, the loggerhead sea turtle Caretta caretta, are the likely culprits of crab pot damage, bait theft, and reduced crab catch, perhaps with important economic impacts. In summer 2005, we conducted a fishing study in cooperation with a pair of crabbers operating one commercial blue crab boat in Core Sound, North Carolina, to characterize location, timing, and extent of damage to crab pots. We examined spatial and temporal overlap of fishing activity with loggerhead sea turtle sightings and quantified blue crab catch. Eighty-seven percent of pots were damaged throughout the course of the study, and gear damage peaked in late June to early July. We measured a 40% reduction in blue crab catch in crab pots that were damaged. Loggerhead sea turtle sightings were consistent with areas of high gear damage. Our results should be considered by managers, who may be able to guide crabbers to concentrate fishing effort at times and areas of reduced overlap with loggerhead sea turtles so as to minimize damage.
The Physiological Response of Port Jackson Sharks and Australian Swellsharks to Sedation, Gill-Net Capture, and Repeated Sampling in Captivity
Authors: Frick Lorenz H. , Reina Richard D. , Walker Terence I.
Published: February 2009

Studying postrelease effects of fisheries capture on chondrichthyans in the wild poses considerable logistical challenges. We report a laboratory-based technique to (1) simulate gill-net capture of sharks, which allows monitoring the condition of animals during recovery from a controlled capture event, and (2) assess effects of sedation, serial blood sampling, and repeated exposure to experimental treatment on stress-related blood variables. Exposing Port Jackson sharks Heterodontus portusjacksoni and Australian swellsharks Cephaloscyllium laticeps to 30 min of simulated gill-net capture elicited behavioral stress (struggling and elevated ventilation rate) and minor physiological stress (elevated plasma lactate) responses but did not cause any mortality. Sedation of Australian swellsharks affected some stress-related blood variables. Repeated handling of Port Jackson sharks and Australian swellsharks at short intervals may result in elevated stress levels, but repeated exposure to simulated capture does not affect the physiological response of these two species to the treatment. Overall, the results of this study demonstrate the feasibility of simulated capture events as a technique to investigate the physiological response of sharks to capture stress.
Effects of Commercial Harvest on Shovelnose Sturgeon Populations in the Upper Mississippi River
Authors: Koch Jeff D. , Quist Michael C. , Pierce Clay L. , Hansen Kirk A. , Steuck Michael J.
Published: February 2009

Shovelnose sturgeon Scaphirhynchus platorynchus have become an increasingly important commercial species in the upper Mississippi River (UMR) because of the collapse of foreign sturgeon (family Acipenseridae) populations and bans on imported caviar. In response to concerns about the sustainability of the commercial shovelnose sturgeon fishery in the UMR, we undertook this study to describe the demographics of the shovelnose sturgeon population and evaluate the influence of commercial harvest on shovelnose sturgeon populations in the UMR. A total of 1,682 shovelnose sturgeon were collected from eight study pools in 2006 and 2007 (Pools 4, 7, 9, 11, 13, 14, 16, and 18). Shovelnose sturgeon from upstream pools generally had greater lengths, weights, and ages than those from downstream pools. Additionally, mortality estimates were lower in upstream pools (Pools 4, 7, 9, and 11) than in downstream pools (Pools 13, 14, 16, and 18). Linear regression suggested that the slower growth of shovelnose sturgeon is a consequence of commercial harvest in the UMR. Modeling of potential management scenarios suggested that a 685-mm minimum length limit is necessary to prevent growth and recruitment overfishing of shovelnose sturgeon in the UMR.
Adipokines in the skeleton: influence on cartilage function and joint degenerative diseases
Authors: Gomez Rodolfo , Lago Francisca , Gomez-Reino Juan , Dieguez Carlos , Gualillo Oreste
Published: February 2009

The discovery of leptin in 1994 marked the beginning of a new understanding about white adipose tissue (WAT) and modified a static vision of this tissue which was viewed up to the end of the 20th century as an inert tissue, devoted to body protection from heat loss and to passively storing energy. The identification of the product of the gene obese accentuated the role of adipose tissue in the physiopathology of obesity-linked diseases, and led to the discovery of various adipokines, many of a pro-inflammatory nature. It has become progressively manifest that WAT-derived adipokines can now be considered as the fulcrum between obesity-related environmental causes, such as nutrition and lifestyle, and the biochemical shifts that lead to metabolic syndrome, inflammatory and/or autoimmune conditions, and rheumatic diseases. Herein, we review recent adipokine research, with particular emphasis to the role of leptin, adiponectin, resistin, and visfatin in chondrocyte function and skeleton, as well as in inflammatory and degenerative cartilage joint diseases.
Briefing: Supply-chain management in the construction industry
Authors: Peat M. , McCrea A.
Published: February 2009

The fundamental and strategic trends that are underway in supply chains need further facilitation and acceleration in the construction industry. This means that management need to review each of these major supply chain trends ȓ outsourcing, collaborating, differentiating and compressing ȓ to determine whether their company lies ahead of, abreast of or behind their competition. Information communication technology (ICT) is an essential aid in the optimisation and improvement of the supply chain management.
The national Fire and Fire Surrogate study: effects of fuel reduction methods on forest vegetation structure and fuels
Authors: Schwilk Dylan W. , Keeley Jon E. , Knapp Eric E. , McIver James , Bailey John D. , Fettig Christopher J. , Fiedler Carl E. , Harrod Richy J. , Moghaddas Jason J. , Outcalt Kenneth W. , Skinner Carl N. , Stephens Scott L. , Waldrop Thomas A. , Yaussy Daniel A. , Youngblood Andrew
Published: February 2009

Changes in vegetation and fuels were evaluated from measurements taken before and after fuel reduction treatments (prescribed fire, mechanical treatments, and the combination of the two) at 12 Fire and Fire Surrogate (FFS) sites located in forests with a surface fire regime across the conterminous United States. To test the relative effectiveness of fuel reduction treatments and their effect on ecological parameters we used an information‐theoretic approach on a suite of 12 variables representing the overstory (basal area and live tree, sapling, and snag density), the understory (seedling density, shrub cover, and native and alien herbaceous species richness), and the most relevant fuel parameters for wildfire damage (height to live crown, total fuel bed mass, forest floor mass, and woody fuel mass).

In the short term (one year after treatment), mechanical treatments were more effective at reducing overstory tree density and basal area and at increasing quadratic mean tree diameter. Prescribed fire treatments were more effective at creating snags, killing seedlings, elevating height to live crown, and reducing surface woody fuels. Overall, the response to fuel reduction treatments of the ecological variables presented in this paper was generally maximized by the combined mechanical plus burning treatment. If the management goal is to quickly produce stands with fewer and larger diameter trees, less surface fuel mass, and greater herbaceous species richness, the combined treatment gave the most desirable results. However, because mechanical plus burning treatments also favored alien species invasion at some sites, monitoring and control need to be part of the prescription when using this treatment.
Fire treatment effects on vegetation structure, fuels, and potential fire severity in western U.S. forests
Authors: Stephens Scott L. , Moghaddas Jason J. , Edminster Carl , Fiedler Carl E. , Haase Sally , Harrington Michael , Keeley Jon E. , Knapp Eric E. , McIver James D. , Metlen Kerry , Skinner Carl N. , Youngblood Andrew
Published: February 2009

Forest structure and species composition in many western U.S. coniferous forests have been altered through fire exclusion, past and ongoing harvesting practices, and livestock grazing over the 20th century. The effects of these activities have been most pronounced in seasonally dry, low and mid‐elevation coniferous forests that once experienced frequent, low to moderate intensity, fire regimes. In this paper, we report the effects of Fire and Fire Surrogate (FFS) forest stand treatments on fuel load profiles, potential fire behavior, and fire severity under three weather scenarios from six western U.S. FFS sites. This replicated, multisite experiment provides a framework for drawing broad generalizations about the effectiveness of prescribed fire and mechanical treatments on surface fuel loads, forest structure, and potential fire severity. Mechanical treatments without fire resulted in combined 1‐, 10‐, and 100‐hour surface fuel loads that were significantly greater than controls at three of five FFS sites. Canopy cover was significantly lower than controls at three of five FFS sites with mechanical‐only treatments and at all five FFS sites with the mechanical plus burning treatment; fire‐only treatments reduced canopy cover at only one site. For the combined treatment of mechanical plus fire, all five FFS sites with this treatment had a substantially lower likelihood of passive crown fire as indicated by the very high torching indices. FFS sites that experienced significant increases in 1‐, 10‐, and 100‐hour combined surface fuel loads utilized harvest systems that left all activity fuels within experimental units. When mechanical treatments were followed by prescribed burning or pile burning, they were the most effective treatment for reducing crown fire potential and predicted tree mortality because of low surface fuel loads and increased vertical and horizontal canopy separation. Results indicate that mechanical plus fire, fire‐only, and mechanical‐only treatments using whole‐tree harvest systems were all effective at reducing potential fire severity under severe fire weather conditions. Retaining the largest trees within stands also increased fire resistance.
A Bayesian modeling approach for determining productivity regimes and their characteristics
Authors: Munch S. B. , Kottas A.
Published: February 2009

Oscillations in the environment result in substantial alterations to population dynamics as evidenced by time series of abundance and recruitment. Depending on the reference timescale, these oscillations are referred to as regime shifts. Regime shifts may occur on very short time scales and are often undetected for several years. Consequently, tools that allow the estimation of regime‐specific population dynamic parameters may be of great value. Using a hidden Markov model to describe the unobserved regime state, we develop methods to infer regime‐specific parameters for a commonly used model of density‐dependent recruitment in addition to identifying the unobserved regime state. We apply the method to recruitment data for Japanese sardine (Sardinops melanostictus).
Managing the impact of invasive species: the value of knowing the density–impact curve
Authors: Yokomizo Hiroyuki , Possingham Hugh P. , Thomas Matthew B. , Buckley Yvonne M.
Published: February 2009

Economic impacts of invasive species worldwide are substantial. Management strategies have been incorporated in population models to assess the effectiveness of management for reducing density, with the implicit assumption that economic impact of the invasive species will also decline. The optimal management effort, however, is that which minimizes the sum of both the management and impact costs. The relationship between population density and economic impact (what we call the “density–impact curve”) is rarely examined in a management context and could take several nonlinear forms. Here we determine the effects of population dynamics and density–impact curves of different shapes on optimal management effort and discover cases where management is either highly effective or a waste of resources. When an inaccurate density–impact curve is used, the increase in total costs due to over‐ or underinvestment in management can be large. We calculate the increase in total costs incurred if the density–impact curve is incorrect and find that the greater the maximum impact caused by an invasive species, the more important it is not only to reduce its density, but also to know the shape of the density–impact relationship accurately. Lack of information regarding the relationship between density and economic impact causes the most acute problems for invaders that cause high impact at low density, where management typically will be too little, too late. For species that are only problematic at high density, ignorance of the density–impact curve can lead to overinvestment in management with little reduction in impact.
Monitoring carbon stocks in the tropics and the remote sensing operational limitations: from local to regional projects
Authors: Sánchez-Azofeifa G. A. , Castro-Esau K. L. , Kurz W. A. , Joyce A.
Published: February 2009

Current remote sensing technologies are effective tools for contributing to the estimation of terrestrial carbon stocks and carbon stock changes. This paper provides an overview of information requirements, sensor capabilities and limitations, and analysis approaches for the use of remotely sensed data in the generation of tropical carbon sequestration monitoring systems. While it is evident that remotely sensed data have tremendous utility for monitoring carbon stock changes, it is important to be aware of their limitations. Three critical limitations are: (1) the definition of methods and algorithms to accurately estimate forest age, (2) the provision of techniques that can yield accurate estimation of deforestation rates in both tropical dry and wet forest environments, and (3) the strong need to develop new approaches to link biophysical variables (e.g., leaf area index) to spectral reflectance to support spatially distributed carbon sequestration models. The validity of final estimates of carbon and carbon stock changes rests on complex issues at several levels, from the data themselves, to the analysis, interpretation, and validation of the data. Consideration of these issues, as well as the need for sound project planning and development within budget constraints, will be important in the development of carbon stock monitoring programs in the tropics.
Climate and desertification: looking at an old problem through new lenses
Authors: Verstraete Michel M , Scholes Robert J , Smith Mark Stafford
Published: February 2009

Global poverty, defined in almost any way, is disproportionately concentrated in the arid, semiarid, and dry subhumid regions – the drylands – of the world. We suggest that the intrinsic biophysical features of these environments, interacting with some social systems that are now no longer appropriate for the changing environment, lead to widespread situations where people living in such areas are trapped in a downward spiral of environmental degradation and loss of well‐being. Externally driven changes in both the social and physical environment, ranging from trade rules to global climate change, contribute to this syndrome. The resultant destabilization of regional climates, ecosystems, hydrological systems, and the social fabric has consequences for neighboring lands as well as the global community. A more holistic set of interventions, that engages both local and global actors, is needed to reverse these negative trends.
Maintaining Medical Independence in Advanced Age
Authors: Barber Ann
Published: February 2009

Juneteenth Day celebrates June 19, 1865, when Major General Granger landed in Texas with news that the Civil War had ended and that slaves were now free (History of Juneteenth, n.d.). Similarly, this article brings you news that patients are free to make their own medical decisions. American law now guarantees the right of all patients to make their own such decisions. Thus, this article introduces the concept of medical policy statements, a new way for patients to give instructions to medical professionals.
Pregnancy-Induced Rise in Serum C-Peptide Concentrations in Women With Type 1 Diabetes
Authors: Nielsen Lene Ringholm , Rehfeld Jens F. , Pedersen-Bjergaard Ulrik , Damm Peter , Mathiesen Elisabeth R.
Published: February 2009

OBJECTIVE

The purpose of this study was to investigate whether pregnancy induces increased insulin production as a marker of improved β-cell function in women with long-term type 1 diabetes.

RESEARCH DESIGN AND METHODS

This was a prospective study of 90 consecutive pregnant women with type 1 diabetes. At 8, 14, 21, 27, and 33 weeks blood samples were drawn for measurements of A1C, C-peptide, and serum glucose. C-peptide (detection limit: 6 pmol/l) was considered stimulated at a corresponding serum glucose concentration ≥5.0 mmol/l. GAD antibody concentration was determined at 8 and 33 weeks in 35 women.

RESULTS

C-peptide concentrations gradually increased throughout pregnancy regardless of serum glucose concentrations in the 90 women with a median duration of diabetes of 17 years (range 1–36 years). Among 35 women with paired recordings of stimulated C-peptide, C-peptide production was detectable in 15 (43%) at 8 weeks and in 34 (97%) at 33 weeks (P < 0.0001), and median C-peptide gradually increased from 6 to 11 pmol/l (P = 0.0004) with a median change of 50% (range −50 to 3,271%) during pregnancy. GAD antibodies were present in 77% with no change from 8 to 33 weeks (P = 0.85). Multivariate regression analysis revealed a positive association between the absolute increase in C-peptide concentrations during pregnancy and decreased A1C from 8 to 33 weeks (P = 0.003).

CONCLUSIONS

A pregnancy-induced increase in C-peptide concentrations in women with long-term type 1 diabetes was demonstrated, even in women with undetectable C-peptide concentrations in early pregnancy. This increase is suggestive of improved β-cell function and was associated with improvement in glycemic control during pregnancy.
Serum Amyloid A, C-Reactive Protein, and Retinal Microvascular Changes in Hypertensive Diabetic and Nondiabetic Individuals
Authors: Stettler Christoph , Witt Nicholas , Tapp Robyn J. , Thom Simon , Allemann Sabin , Tillin Therese , Stanton Alice , O'Brien Eoin , Poulter Neil , Gallimore J. Ruth , Hughes Alun D. , Chaturvedi Nish
Published: February 2009

OBJECTIVE

To study the association of the inflammatory markers serum amyloid A (SAA) and C-reactive protein (CRP) with retinal microvascular parameters in hypertensive individuals with and without type 2 diabetes.

RESEARCH DESIGN AND METHODS

This cross-sectional analysis was a substudy in 711 patients (159 with and 552 without diabetes) of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT) based on digital 30-degree images of superior and inferior temporal retinal fields.

RESULTS

SAA was associated with arteriolar length-to-diameter ratio positively in nondiabetic patients (Ptrend= 0.028) but negatively in diabetic patients (Ptrend= 0.005). The difference was unlikely to be a chance finding (P = 0.007 for interaction). Similar results were found for the association of SAA with arteriolar tortuosity (P = 0.05 for interaction). Associations were less pronounced for CRP and retinal parameters.

CONCLUSIONS

Inflammatory processes are differentially involved in retinal microvascular disease in diabetic compared with nondiabetic hypertensive individuals.
Abdominal Subcutaneous Adipose Tissue: A Protective Fat Depot?
Authors: Porter Stacy A. , Massaro Joseph M. , Hoffmann Udo , Vasan Ramachandran S. , O'Donnel Christopher J. , Fox Caroline S.
Published: February 2009

OBJECTIVE

Obesity is associated with increased metabolic and cardiovascular risk. The ectopic fat hypothesis suggests that subcutaneous fat may be protective, but this theory has yet to be fully explored.

RESEARCH DESIGN AND METHODS

Participants from the Framingham Heart Study (n = 3,001, 48.5% women) were stratified by visceral adipose tissue (VAT) into sex-specific tertiles. Within these tertiles, age-adjusted abdominal subcutaneous adipose tissue (SAT) tertiles were examined in relation to cardiometabolic risk factors.

RESULTS

In the lowest VAT tertile, risk factor prevalence was low, although systolic blood pressure in women and rates of high triglycerides, impaired fasting glucose, hypertension, and the metabolic syndrome in men increased with increasing SAT tertile (all P < 0.04). In contrast, in the top VAT tertile, lower triglycerides were observed in men with increasing SAT (64.4% high triglycerides in SAT tertile 1 vs. 52.7% in SAT tertile 3, P = 0.03). Similar observations were made for women, although results were not statistically significant (50.6% high triglycerides in SAT tertile 1 vs. 41.0% in tertile 3, P = 0.10). Results in the highest VAT tertile were notable for a lack of increase in the prevalence of low HDL in men and women and in rates of impaired fasting glucose in men with increasing subcutaneous fat, despite sizable differences in BMI across SAT tertiles (27.1 to 36.3 kg/m2[women]; 28.1 to 35.7 kg/m2[men]).

CONCLUSIONS

Although adiposity increases the absolute risk of metabolic and cardiovascular disease, abdominal subcutaneous fat is not associated with a linear increase in the prevalence of all risk factors among the obese, most notably, high triglycerides.
Environmental Enrichment Induces Synaptic Structural Modification After Transient Focal Cerebral Ischemia in Rats
Authors: Xu Xiaohong , Ye Lingjing , Ruan Qin
Published: February 2009

Environmental enrichment (EE), where animals are exposed to a complex novel environment, has been shown to induce synaptic plasticity in both intact and injured animals. The purpose of this study was to investigate the effects of EE on spatial memory and structural modifications of synaptic junctions in rats following transient focal cerebral ischemia. Adult male Sprague-Dawley rats underwent right middle cerebral artery occlusion (MCAO) for 40 min and reperfusion. On day 3 after MCAO or sham surgery, rats were randomly assigned for 14 days to enriched or standard environmental housing. Spatial memory was then tested by the Morris water maze. Parietal cortex and the CA1 region of hippocampus were processed for electron microscopy and stereological techniques were used to evaluate plasticity of synaptic junctions. EE after MCAO improved spatial memory, with shortened escape length, increased frequency of crossings at the location of the platform, and increased percentage of time spent in the quadrant where the platform was previously located. Synaptic ultrastructural analysis showed that EE after MCAO increased numeric synaptic density in parietal cortex, and induced structural changes in synaptic junctions, with a decreased width of synaptic clefts and increased thickness of postsynaptic densities (PSD) in parietal cortex and hippocampus, accompanying improved performance on the spatial memory task. Using Western blot analysis, we determined the expression of glutamate receptor NMDAR1, and PSD-95, the best characterized protein member of the PSD-95 family, that was abundantly expressed in the PSD of excitatory synapses. The results showed that the content of NMDAR1 was not altered in MCAO rats of EE; however, the phosphorylated NMDAR1 increased significantly when compared with the standard environment housing MCAO rats. In addition, EE inhibited the impaired expression of PSD-95 induced by MCAO in parietal cortex and hippocampus. These data suggest that improved spatial memory of cerebral ischemic rats by EE is associated with structural modifications of synaptic junctions in several brain regions.
The Sanctity of the City of ‘Asqalan in the ‘Merits Literature’ of Palestine: An Examination of Mamluk and Ottoman Sources
Authors: Anabseh Ghaleb
Published: February 2009

The purpose of this study is to analyse the sanctity of the Palestine city of ‘Asqalan through manuscript sources from Mamluk and Ottoman times, mainly from a religious and political perspective, in light of the struggle between Muslims and Crusaders. Relevant traditions are often of a local nature, expressing concepts completely at odds with normative Islamic practice and belief. No separate compositions have been compiled about ‘Asqalan, in contrast to Jerusalem and Damascus, for example. Pilgrimage to the city was frowned upon by the Hanbali school of jurisprudence within Sunni Islam, represented by Ibn Taymiyya in the Mamluk period. Relevant traditions deal with war against the infidels, the city's cemetery, the city as gateway to Paradise, and more. For this study I have used the relevant traditions in the genre known as ‘Merits of the Holy Land’, in Arabic from Mamluk and Ottoman times. These traditions reflect the sanctity of ‘Asqalan; some have ancient Islamic roots, and others appeared later. The traditions in question, whenever they were first formulated, show the importance of the city for Muslim writers.