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High Vulnerability (high + vulnerability)
Selected AbstractsProbability distributions, vulnerability and sensitivity in Fagus crenata forests following predicted climate changes in JapanJOURNAL OF VEGETATION SCIENCE, Issue 5 2004Tetsuya Matsui Question: How much is the probability distribution of Fagus crenata forests predicted to change under a climate change scenario by the 2090s, and what are the potential impacts on these forests? What are the main factors inducing such changes? Location: The major islands of Japan. Methods: A predictive distribution model was developed with four climatic factors (summer precipitation, PRS; winter precipitation, PRW; minimum temperature of the coldest month, TMC; and warmth index, WI) and five non-climatic factors (topography, surface geology, soil, slope aspect and inclination). A climate change scenario was applied to the model. Results: Areas with high probability (> 0.5) were predicted to decrease by 91%, retreating from the southwest, shrinking in central regions, and expanding northeastwards beyond their current northern limits. A vulnerability index (the reciprocal of the predicted probability) suggests that Kyushu, Shikoku, the Pacific Ocean side of Honshu and southwest Hokkaido will have high numbers of many vulnerable F. crenata forests. The forests with high negative sensitivity indices (the difference between simulated probabilities of occurrence under current and predicted climates) mainly occur in southwest Hokkaido and the Sea of Japan side of northern Honshu. Conclusion: F. crenata forest distributions may retreat from some islands due to a high WI. The predicted northeastward shift in northern Hokkaido is associated with increased TMC and PRS. High vulnerability and negative sensitivity of the forests in southern Hokkaido are due to increased WI. [source] New onsets of substance use disorders in borderline personality disorder over 7 years of follow-ups: findings from the Collaborative Longitudinal Personality Disorders StudyADDICTION, Issue 1 2009Marc Walter ABSTRACT Aims The purpose of this study was to examine whether patients with borderline personality disorder (BPD) have a higher rate of new onsets of substance use disorders (SUD) than do patients with other personality disorders (OPD). Design This study uses data from the Collaborative Longitudinal Personality Disorder Study (CLPS), a prospective naturalistic study with reliable repeated measures over 7 years of follow-up. Setting Multiple clinical sites in four northeastern US cities. Participants A total of 175 patients with BPD and 396 patients with OPD (mean age 32.5 years) were assessed at baseline and at 6, 12, 24, 36, 48, 60, 72 and 84 months. Measurements The Structured Clinical Interview for DSM-IV Axis I Disorders and the Diagnostic Interview for DSM-IV Personality Disorders were used at baseline, the Follow-Along version of the DIPD-IV and the Longitudinal Interval Follow-up Evaluation at the follow-up evaluations. Kaplan,Meier analyses were calculated to generate the time to new onsets. Findings BPD patients showed a shorter time to new onsets of SUD. Thirteen per cent of BPD patients developed a new alcohol use disorder and 11% developed a new drug use disorder, compared to rates of 6% and 4%, respectively, for OPD. Non-remitted BPD and remitted BPD patients did not differ significantly in rates of new onsets of SUD. Conclusions BPD patients have a high vulnerability for new onsets of SUDs even when their psychopathology improves. These findings indicate some shared etiological factors between BPD and SUD and underscore the clinical significance of treating SUD when it co-occurs in BPD patients. [source] GENETIC STUDY: 5-HTTLPR polymorphism, mood disorders and MDMA use in a 3-year follow-up studyADDICTION BIOLOGY, Issue 1 2010Rocío Martín-Santos ABSTRACT A 3-year longitudinal prospective study was conducted to compare the incidence of substance use disorders (SUD) and non-substance use disorders (NSUD) among ecstasy users and two control groups: one of cannabis users and the other of non-drug users. The 5-HTTLPR polymorphism related to NSUD was also studied. A total of 94 subjects were included: 37 ecstasy users, 23 cannabis users and 34 non-drug users. SUD and NSUD disorders were diagnosed according to the fourth edition of the Diagnostic and Statistical Manual of Mental Health Disorders criteria using the Psychiatric Research Interview for Substance and Mental Disorders. Incidence Rates (IR) are presented. The 5-HTTLPR polymorphism was analyzed. Hardy,Weinberg equilibrium was studied. The results of the study showed that the highest IR of SUD was cannabis abuse/dependence in both the ecstasy (IR: 48.6/100 person,year) and cannabis (IR: 2.5/100 person,year) groups. There were no new cases of SUD in non-drug users at follow-up. The highest IR of NSUD was primary mood disorder in both the ecstasy (IR: 4.2/100 person,year) and in the non-drug (IR: 1.3/100 person,year) groups (P < 0.282). There were no new cases of NSUD in the cannabis group at follow-up. 5-HTTLPR polymorphism was associated with lifetime of primary mood disorders in ecstasy group (P = 0.018). Ecstasy use was associated with a higher rate of cannabis abuse/dependence disorders and mood disorders than cannabis use. In the ecstasy users, 5-HTTLPR polymorphism may result in a high vulnerability to primary mood disorders. [source] Glial cells promote dendrite formation and the reception of synaptic input in Purkinje cells from postnatal miceGLIA, Issue 5 2010Isabelle Buard Abstract Previous studies suggest that glial cells contribute to synaptogenesis in specific neurons from the postnatal CNS. Here, we studied whether this is true for Purkinje cells (PCs), which represent a unique neuronal cell type due to their large size, massive synaptic input, and high vulnerability. Using new glia-free cultures enriched in PCs from postnatal mice we show that these neurons survived and grew, but displayed only low levels of excitatory and inhibitory synaptic activity. Coculture with glial cells strongly enhanced the frequency and size of spontaneous and miniature excitatory synaptic currents as well as neurite growth and branching. Immunocytochemical staining for microtubule-associated protein 2- (MAP2-) positive neurites revealed impaired dendrite formation in PCs under glia-free conditions, which can explain the absence of synaptic activity. Glial signals strongly enhanced dendritogenesis in PCs and thus their ability to receive excitatory synaptic input from granule cells (GCs). The enhancement of dendrite formation was mimicked by glia-conditioned medium (GCM), whereas the increase in synaptic activity required physical presence of glia. This indicated that dendrite development is necessary but not sufficient for PCs to receive excitatory synaptic input and that synaptogenesis requires additional signals. The level of inhibitory synaptic activity was low even in cocultures due to a low incidence of inhibitory interneurons. Taken together, our results reinforce the idea that glial cells promote synaptogenesis in specific neuronal cell types. © 2009 Wiley-Liss, Inc. [source] The verification and application of bioindicators: a case study of dung beetles in a savanna ecosystemJOURNAL OF APPLIED ECOLOGY, Issue 4 2002Melodie A. McGeoch Summary 1Bioindicators of habitat quality and environmental change must be identified quantitatively and tested independently to confirm their usefulness. We used the indicator value (IndVal) method, which combines measures of habitat fidelity and specificity, to assess the indicator responses of dung beetles (Coleoptera: Scarabaeidae) in Tembe Elephant Park, South Africa. The indicator responses were verified by sampling in different areas of the Park, 2 years after the responses were originally quantified. 2We postulated that terrestrial insect indicators with different combinations of habitat specificity and fidelity might fulfil different indicator roles. Indicator species with strong habitat specificity (characteristic species) are unlikely to provide information on the direction of ecological change despite high vulnerability. Rather, detector species that span a range of ecological states are likely to be better in this role. We used IndVal for selecting such detector species that indicate the direction of ecological change. 3Sets of species were found to be robust bioindicators, i.e. reliably characteristic across the habitat of which they were indicative. The suite of indicators was refined by discarding those with IndVals that varied significantly across years, thus improving the confidence in the final suite of species selected. By clearly responding to a change in habitat between two ecological states, detector species provided information complementary to that provided by characteristic species. 4The IndVal method enabled both the identification and testing of indicator (characteristic and detector) species. Because of its resilience to changes in abundance, IndVal is a particularly effective tool for ecological bioindication. 5We conclude that both characteristic and detector species are useful bioindicators of habitat quality and conversion. We propose that bioindicators that are categorized and verified in this way will have valuable application in the monitoring of habitat integrity. [source] Testing liana cutting and controlled burning as silvicultural treatments for a logged forest in the eastern AmazonJOURNAL OF APPLIED ECOLOGY, Issue 6 2001Jeffrey J. Gerwing Summary 1In the eastern Brazilian Amazon, logged forests frequently include patches where liana density is particularly high. In these so-called liana tangles, competition from lianas is predicted to reduce tree growth significantly, thus effectively impeding future timber production. To begin to develop a silvicultural strategy for these patches, the impact of liana cutting and controlled burning on liana density, tree growth and tree regeneration in liana-dominated patches was investigated in a logged forest in the eastern Brazilian Amazon. 2The two treatments (liana cutting and controlled burning) and a control were installed in 40 × 40-m plots in a randomized complete block design of six blocks. Treatments were conducted during October 1997, and tree diameter growth and mortality, canopy cover, regeneration and liana density were monitored over 2 years. 3Mean mortality following burning was significantly higher for lianas (79%) than for trees (48%), as was the mean coppicing rate of top-killed stems (42% for lianas vs. 20% for trees). Coppicing combined with some recruitment from seed resulted in liana densities in the burned plots returning to 70% of the values in the control plots only 2 years post-treatment. 4Canopy light transmittance, estimated from hemispherical canopy photographs taken at 1 m above the ground, increased significantly from c. 4% in controls to 8% in cut and 12% in burned treatments, and these differences persisted over the 2-year study period. 5In the absence of silvicultural intervention, mean tree diameter increments were low (1·3 mm year,1), suggesting that the successional transition to higher stature forest was occurring very slowly. Each of the treatments resulted in a more than doubling of mean annual tree growth (3 and 2·8 mm year,1 for liana-cut and burned treatments, respectively). The treatments also significantly reduced the occurrence of trees that showed no growth over the study period, from 56% in controls to 30% in cut and 32% in burned treatments. 6The results of this study suggest that although burning resulted in increased tree growth, rapid recolonization of surviving trees by lianas and the high vulnerability of burned stands to unwanted repeat burns are likely to cancel out any of the possible benefits of controlled burning as a silvicultural treatment for liana-dominated patches. Liana cutting, on the other hand, showed promise and its adoption as part of a larger strategy for the recuperation of the timber production potential of logged tropical forests seems warranted. [source] Hunting, disturbance and roost persistence of bats in caves at Ankarana, northern MadagascarAFRICAN JOURNAL OF ECOLOGY, Issue 4 2009Scott G. Cardiff Abstract Surveys and monitoring of 37 caves in and around the Ankarana Special Reserve, northern Madagascar, yielded evidence of hunting of bats and potential disturbance of bats by miners and tourists, and colony counts for several bat species of potential conservation concern. Colony size decreased by 95% and 14% for a colony of Hipposideros commersoni and a colony of Eidolon dupreanum, respectively, when recent evidence of hunting occurred at those colonies and those declines are probably attributable to hunting. Evidence of hunting occurred commonly at the roosts of those species and most commonly at the roosts of Rousettus madagascariensis. Hunting of pteropodids was associated with high vulnerability of roosts to hunters, little forest buffer between the cave and open savannah and the absence of tombs in the cave. Roost sites of the hunted species persisted for at least several years and this regularity may facilitate hunting. This work supports the ranking of E. dupreanum, R. madagascariensis and H. commersoni as species of conservation concern. Managers should consider the impact of tourist visits on bats and of increasing access to caves for tourism. Conservation efforts for the hunted species should also seek to protect vulnerable and unprotected cave roosts. Résumé Des études et un suivi continu de 37 grottes dans la Réserve Spéciale d'Ankarana et dans les environs, dans le nord de Madagascar, ont permis de récolter des preuves de la chasse aux chauves-souris et de l'éventuel dérangement des chauves-souris par des mineurs et des touristes; et des comptes de colonies pour plusieurs espèces dont le statut de conservation pourrait être inquiétant. La taille des colonies avait baissé de 95% et de 14% respectivement pour Hipposideros commersoni et pour Eidolon dupreanum, lorsque des preuves récentes de chasse sont apparues dans ces colonies; ces déclins sont probablement dus à la chasse. Des preuves de chasse étaient réguliérement présentes aux dortoirs de ces espèces, et plus communes encore aux dortoirs de Rousettus madagascariensis. La chasse des ptéropodidés était associée à une grande vulnérabilité des dortoirs face aux chasseurs, à une petite zone forestière tampon entre la grotte et la savane ouverte, et à l'absence de tombes dans la grotte. Les sites de repos des espèces chassées existaient depuis plusieurs années au moins, et cette persistance pourrait faciliter la chasse. Ce travail soutient le classement de E. dupreanum, R. madagascariensis et H. commersoni parmi les espèces dont le statut de conservation est inquiétant. Les gestionnaires devraient considérer l'impact des visites de touristes sur les chauves-souris et de l'augmentation de l'accès aux grottes pour le tourisme. Les efforts de conservation des espèces chassées devraient aussi viser à protéger les dortoirs dans des grottes vulnérables et non protégées. [source] Glutamate-mediated influx of extracellular Ca2+ is coupled with reactive oxygen species generation in cultured hippocampal neurons but not in astrocytesJOURNAL OF NEUROSCIENCE RESEARCH, Issue 1-2 2005Stefan Kahlert Abstract Generation of reactive oxygen species (ROS) in brain tissue leads to neurodegeneration. The major source of ROS is the mitochondrial respiratory chain. We studied regulation of Ca2+ level, mitochondrial potential, and ROS generation in defined mixed hippocampal cell cultures exposed to glutamate (100 ,M). Recordings were made from individually identified astrocytes and neurons to compare the physiologic responses in both cell types. Neurons identified by synaptotagmin immunoreactivity were characterized functionally by the fast Ca2+ increase with K+ (50 mM) stimulation, and the astrocytes identified by glial fibrillary acidic protein (GFAP) staining had the functional characteristic of a transient Ca2+ peak in response to ATP (10 ,M) stimulation. We found that the glutamate-mediated Ca2+ response in neurons is due largely to influx of extracellular Ca2+. This is consistent with our finding that in cultured hippocampal neurons, stores depending on the activity of the sarcoendoplasmic reticulum Ca2+ ATPase (SERCA) pump had a low Ca2+ content, regardless of whether the neurons were challenged or not with K+ before applying the SERCA inhibitor cyclopiazonic acid (CPA). Astrocytes displayed a large CPA-mediated Ca2+ response, indicating a high level of Ca2+ load in the stores in astrocytes. Importantly, the rise in ROS generation due to glutamate application was cell-type specific. In neurons, glutamate induced a marked rise in generation of ROS, but not in astrocytes. In both astrocytes and neurons, the mitochondrial potential was increased in response to glutamate challenge. We conclude that in neurons, Ca2+ influx accounts for the increased ROS generation in response to glutamate. This might explain the high vulnerability of neurons to glutamate challenge compared to the vulnerability of astrocytes. The high resistance of astrocytes is accompanied by an efficient downregulation of cytosolic Ca2+, which is not found in neurons. © 2004 Wiley-Liss, Inc. [source] Low sensitivity of retina to AMPA-induced calcificationJOURNAL OF NEUROSCIENCE RESEARCH, Issue 4 2003Noemí Andrés Abstract Glutamate is involved in most CNS neurodegenerative diseases. In particular, retinal diseases such as retinal ischemia, retinitis pigmentosa, and diabetic retinopathy are associated with an excessive synaptic concentration of this neurotransmitter. To gain more insight into retinal excitotoxicity, we carried out a dose,response study in adult rats using ,-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA), a glutamate analogue. AMPA intraocular injections (between 0.27 and 10.8 nmol) caused no morphologic modification, but a 10.8 + 21 nmol double injection in a 10-day interval produced a lesion characterized by discrete neuronal loss, astroglial and microglial reactions, and calcium precipitation. Abundant calcium deposits similar to those present in rat and human brain excitotoxicity or hypoxia-ischemia neurodegeneration were detected by alizarin red staining within the retinal surface and the optic nerve. Glial reactivity, associated normally with astrocytes in the nerve fiber, was assessed in Müller cells. GABA immunoreactivity was detected not only in neuronal elements but also in Müller cells. In contrast to the high vulnerability of the brain to excitotoxin microinjection, AMPA-induced retinal neurodegeneration may provide a useful model of low central nervous system sensitivity to excitotoxicity. © 2003 Wiley-Liss, Inc. [source] What causes the vulnerability of endemic animals?JOURNAL OF ZOOLOGY, Issue 2 2004A case study from Sri Lanka Abstract Around the world, endemic species with restricted ranges seem to be at particular risk of extinction. When range size is controlled, lowland continental species may be especially at risk, more so than island or montane species. Our study aimed to investigate reasons behind the high vulnerability of endemic species. In Sri Lanka, large-scale national surveys and intensive localized fieldwork established that endemic plant and animal species are mostly associated with undisturbed rainforest habitats. On the other hand, non-endemic species used both forest and non-forest habitats almost equally, suggesting they are less likely to suffer from deleterious edge effects. To understand the different distribution of endemic and non-endemic species, our study focused on rats. Compared to the widespread species, the endemic rat species had a larger home range and fed on fewer species of forest fruit, possibly indicating greater specialization. The abundance of the endemic species was also negatively correlated with the abundance of the non-endemic species, to which it was behaviourally subordinate. Greater specialization and competitive inferiority could both contribute to the vulnerability of endemic species. [source] Quantifizierung der Schäden infolge Hochwassereinwirkung: Fallstudie EilenburgBAUTECHNIK, Issue 12 2005Jochen Schwarz Dr.-Ing. Die für das Katastrophenmanagement notwendige Abschätzung der Schäden unter Hochwassereinwirkung ist eine entscheidende, aber bislang methodisch-wissenschaftlich noch unzureichend vorbereitete Aufgabenstellung. In Anlehnung an die für die Risikoanalyse Erdbeben entwickelte Vorgehensweise wird überprüft, inwieweit methodische Grundlagen übernommen werden können bzw. modifiziert werden müssen, und welche Kenngrößen aus Datenerhebungen abzuleiten sind. Dabei wird neben der Hochwassereinwirkung in Form der Überflutungshöhe als wesentliche Neuerung der Einfluß der Bauwerksparameter berücksichtigt. Die Bauweisen sind danach in Verletzbarkeitsklassen einzuordnen, denen einwirkungsabhängig charakteristische strukturelle Schäden bzw. Durchfeuchtungsgrade zugewiesen werden können, die letztlich auch die Höhe des Schadens (Kosten) bestimmen. Wie anhand der Fallstudie Eilenburg gezeigt werden kann, können mit dem gewählte Ansatz für ein vorgegebenes Szenarium Gebiete mit besonders verletzbarer Bauwerksstruktur identifiziert und Empfehlungen für künftige Bebauung abgeleitet werden. Ein Schlüsselelement in der Vorgehensweise liegt in der Aufbereitung der erforderlichen bzw. geeigneten Datenebenen, die über Schadensfunktionen zu verknüpfen sind. Der Beitrag gibt eine Übersicht zu den Vorgehensweisen im mesoskaligen und mikroskaligen Betrachtungsmaßstab. Wie am Beispiel der Stadt Eilenburg gezeigt wird, können mit den bereitgestellten ingenieurmäßigen Hilfsmitteln und Datenebenen die aufgetretenen Schäden durch das Hochwasser 2002 in ihrer Höhe und Verteilung reinterpretiert werden. Assessment of damage due to flood impact: the case study of Eilenburg. Estimating damage caused by flood impact is an important, yet scientifically and methodically insufficiently investigated task, which is necessary for preparing the management of catastrophes. Alluding to the procedure developed in the risk analysis of earthquakes it is checked, whether methodical fundamentals can be transferred or have to be modified, and which parameters must be derived from data surveys. As an essential improvement, in addition to the inundation level, the influence of the buildings' parameters are considered. Subsequently, the building types are sorted into vulnerability classes, to which characteristic structural damages, depending on the impact, or humidity penetration ratios can be assigned, which ultimately determine the extent of the damage and the resulting cost. As can be shown for the case study of Eilenburg, areas with unusually high vulnerability of the building stock can be identified by applying the chosen approach assuming a defined scenario, leading to recommendations for future decisions on building in the area. A key element of the procedure lies in the preparation of the required or, respectively, usable data, which must be linked by damage functions. The paper gives an overview of the approaches for observations on mesoscale and microscale. As can be shown on the example of the town Eilenburg, with the provided tools and data, the damages caused by the flood in August 2002 can be reinterpreted regarding their height and distribution. [source] | ||||||||||