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Showing papers by "University of Bergen published in 2002"


Journal ArticleDOI
TL;DR: HADS was found to perform well in assessing the symptom severity and caseness of anxiety disorders and depression in both somatic, psychiatric and primary care patients and in the general population.

8,477 citations


Journal ArticleDOI
TL;DR: This review summarizes the recent progress in studies of soil microbial communities with focus on novel methods and approaches that provide new insight into the relationship between phylogenetic and functional diversity.

1,728 citations


Journal ArticleDOI
TL;DR: Evidence is provided that widespread DNA copy number alteration can lead directly to global deregulation of gene expression, which may contribute to the development or progression of cancer.
Abstract: Genomic DNA copy number alterations are key genetic events in the development and progression of human cancers. Here we report a genome-wide microarray comparative genomic hybridization (array CGH) analysis of DNA copy number variation in a series of primary human breast tumors. We have profiled DNA copy number alteration across 6,691 mapped human genes, in 44 predominantly advanced, primary breast tumors and 10 breast cancer cell lines. While the overall patterns of DNA amplification and deletion corroborate previous cytogenetic studies, the high-resolution (gene-by-gene) mapping of amplicon boundaries and the quantitative analysis of amplicon shape provide significant improvement in the localization of candidate oncogenes. Parallel microarray measurements of mRNA levels reveal the remarkable degree to which variation in gene copy number contributes to variation in gene expression in tumor cells. Specifically, we find that 62% of highly amplified genes show moderately or highly elevated expression, that DNA copy number influences gene expression across a wide range of DNA copy number alterations (deletion, low-, mid- and high-level amplification), that on average, a 2-fold change in DNA copy number is associated with a corresponding 1.5-fold change in mRNA levels, and that overall, at least 12% of all the variation in gene expression among the breast tumors is directly attributable to underlying variation in gene copy number. These findings provide evidence that widespread DNA copy number alteration can lead directly to global deregulation of gene expression, which may contribute to the development or progression of cancer.

1,258 citations


Journal ArticleDOI
10 May 2002-Science
TL;DR: There are probably millions of species in the microorganismal domains Bacteria and Archaea (the prokaryotes), and the authors are only just beginning to work out the basic principles governing their distribution and abundance in natural environments.
Abstract: There are probably millions of species in the microorganismal domains Bacteria and Archaea (the prokaryotes), and we are only just beginning to work out the basic principles governing their distribution and abundance in natural environments. One characteristic that has become clear is that prokaryote diversity in aquatic environments is orders of magnitude less than in sediments and soils. Hypotheses and models explaining such differences are under development and are beginning to offer promising insights into the mechanisms governing prokaryote diversity and ecosystem function.

1,150 citations


Journal ArticleDOI
TL;DR: Losartan was significantly better tolerated than captopril, with fewer patients discontinuing study medication (458 [17%] vs 624 [23%], 0·70 [0·62-0·79], p=0·72.

1,069 citations


Journal ArticleDOI
TL;DR: The contention that articular cartilage defects are common in patients with symptomatic knees requiring arthroscopy is supported, and the prevalence of patients who might benefit from cartilage repair surgery is calculated.
Abstract: Purpose: Focal chondral or osteochondral defects can be painful and disabling, have a poor capacity for repair, and may predispose patients for osteoarthritis. New surgical procedures that aim to reestablish hyaline cartilage have been introduced and the results seem promising. The purpose of this study is to provide reliable data on chondral and osteochondral defects in patients with symptomatic knees requiring arthroscopy and to calculate the prevalence of patients who might benefit from cartilage repair surgery. Type of Study: Prospective study. Methods: One thousand consecutive knee arthroscopies were included in this study. Immediately after each arthroscopy, the surgeon completed a questionnaire providing detailed information about the findings. Chondral and osteochondral lesions were classified in accordance with the system recommended by the International Cartilage Repair Society (ICRS). Results: Chondral or osteochondral lesions (of any type) were found in 61% of the patients. Focal chondral or osteochondral defects were found in 19% of the patients. In these patients, 61% related their current knee problem to a previous trauma, and a concomitant meniscal or anterior cruciate ligament injury was found in 42% (n = 81) and 26% (n = 50), respectively. The mean chondral or osteochondral total defect area was 2.1 cm 2 (range, 0.5 to 12; standard deviation [SD], 1.5). The main focal chondral or osteochondral defect was found on the medial femoral condyle in 58%, patella in 11%, lateral tibia in 11%, lateral femoral condyle in 9%, trochlea in 6%, and medial tibia in 5%. It has been suggested that cartilage repair surgery may be most suitable in patients younger than 40 to 50 years old. A single, well-defined ICRS grade III or IV defect with an area of at least 1 cm 2 in a patient younger than 40, 45, or 50 years accounted for 5.3%, 6.1%, and 7.1% of all arthroscopies, respectively. Conclusions: Our study supports the contention that articular cartilage defects are common. It has the advantages of a prospective design and use of a new classification system recommended by the ICRS. This modern system focuses on objectively measurable parameters of the lesion's extent and not its surface appearance. Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 18, No 7 (September), 2002: pp 730–734

815 citations


Journal ArticleDOI
Bernard Aubert, A. Bazan, A. Boucham, D. Boutigny  +816 moreInstitutions (68)
TL;DR: BABAR as discussed by the authors is a detector for the SLAC PEP-II asymmetric e+e-B Factory operating at the upsilon 4S resonance, which allows comprehensive studies of CP-violation in B-meson decays.
Abstract: BABAR, the detector for the SLAC PEP-II asymmetric e+e- B Factory operating at the upsilon 4S resonance, was designed to allow comprehensive studies of CP-violation in B-meson decays. Charged particle tracks are measured in a multi-layer silicon vertex tracker surrounded by a cylindrical wire drift chamber. Electromagentic showers from electrons and photons are detected in an array of CsI crystals located just inside the solenoidal coil of a superconducting magnet. Muons and neutral hadrons are identified by arrays of resistive plate chambers inserted into gaps in the steel flux return of the magnet. Charged hadrons are identified by dE/dx measurements in the tracking detectors and in a ring-imaging Cherenkov detector surrounding the drift chamber. The trigger, data acquisition and data-monitoring systems, VME- and network-based, are controlled by custom-designed online software. Details of the layout and performance of the detector components and their associated electronics and software are presented.

789 citations


Journal ArticleDOI
TL;DR: It is shown that one intronic SNP in PDCD1 is associated with development of SLE in Europeans, and this SNP alters a binding site for the runt-related transcription factor 1 (RUNX1) located in an intronic enhancer, suggesting a mechanism through which it can contribute to the development ofSLE in humans.
Abstract: Systemic lupus erythematosus (SLE, OMIM 152700) is a complex autoimmune disease that affects 0.05% of the Western population, predominantly women. A number of susceptibility loci for SLE have been suggested in different populations, but the nature of the susceptibility genes and mutations is yet to be identified. We previously reported a susceptibility locus (SLEB2) for Nordic multi-case families. Within this locus, the programmed cell death 1 gene (PDCD1, also called PD-1) was considered the strongest candidate for association with the disease. Here, we analyzed 2,510 individuals, including members of five independent sets of families as well as unrelated individuals affected with SLE, for single-nucleotide polymorphisms (SNPs) that we identified in PDCD1. We show that one intronic SNP in PDCD1 is associated with development of SLE in Europeans (found in 12% of affected individuals versus 5% of controls; P = 0.00001, r.r. (relative risk) = 2.6) and Mexicans (found in 7% of affected individuals versus 2% of controls; P = 0.0009, r.r. = 3.5). The associated allele of this SNP alters a binding site for the runt-related transcription factor 1 (RUNX1, also called AML1) located in an intronic enhancer, suggesting a mechanism through which it can contribute to the development of SLE in humans.

775 citations


Journal ArticleDOI
TL;DR: The results support a model in which BDNF triggers long-lasting synaptic strengthening through MEK-ERK and selective induction of the dendritic mRNA speciesArc, and in situ hybridization showed that Arc transcripts are rapidly and extensively delivered to granule cell dendrites.
Abstract: Brain-derived neurotrophic factor (BDNF) is implicated in long-term synaptic plasticity in the adult hippocampus, but the cellular mechanisms are little understood. Here we used intrahippocampal microinfusion of BDNF to trigger long-term potentiation (BDNF-LTP) at medial perforant path--granule cell synapses in vivo. BDNF infusion led to rapid phosphorylation of the mitogen-activated protein (MAP) kinases ERK (extracellular signal-regulated protein kinase) and p38 but not JNK (c-Jun N-terminal protein kinase). These effects were restricted to the infused dentate gyrus; no changes were observed in microdissected CA3 and CA1 regions. Local infusion of MEK (MAP kinase kinase) inhibitors (PD98059 and U0126) during BDNF delivery abolished BDNF-LTP and the associated ERK activation. Application of MEK inhibitor during established BDNF-LTP had no effect. Activation of MEK-ERK is therefore required for the induction, but not the maintenance, of BDNF-LTP. BDNF-LTP was further coupled to ERK-dependent phosphorylation of the transcription factor cAMP response element-binding protein. Finally, we investigated the expression of two immediate early genes, activity-regulated cytoskeleton-associated protein (Arc) and Zif268, both of which are required for generation of late, mRNA synthesis-dependent LTP. BDNF infusion resulted in selective upregulation of mRNA and protein for Arc. In situ hybridization showed that Arc transcripts are rapidly and extensively delivered to granule cell dendrites. U0126 blocked Arc upregulation in parallel with BDNF-LTP. The results support a model in which BDNF triggers long-lasting synaptic strengthening through MEK-ERK and selective induction of the dendritic mRNA species Arc.

754 citations


Journal ArticleDOI
TL;DR: A novel cAMP analogue is developed, 8CPT-2Me-cAMP, which activates Epac, but not PKA, both in vitro and in vivo, and tests the widespread model that Rap1 mediates cAMP-induced regulation of the extracellular signal-regulated kinase (ERK).
Abstract: cAMP is involved in a wide variety of cellular processes that were thought to be mediated by protein kinase A (PKA)1. However, cAMP also directly regulates Epac1 and Epac2, guanine nucleotide-exchange factors (GEFs) for the small GTPases Rap1 and Rap2 (refs 2,3). Unfortunately, there is an absence of tools to discriminate between PKA- and Epac-mediated effects. Therefore, through rational drug design we have developed a novel cAMP analogue, 8-(4-chloro-phenylthio)-2′-O-methyladenosine-3′,5′-cyclic monophosphate (8CPT-2Me-cAMP), which activates Epac, but not PKA, both in vitro and in vivo. Using this analogue, we tested the widespread model that Rap1 mediates cAMP-induced regulation of the extracellular signal-regulated kinase (ERK)4,5. However, both in cell lines in which cAMP inhibits growth-factor-induced ERK activation and in which cAMP activates ERK, 8CPT-2Me-cAMP did not affect ERK activity. Moreover, in cell lines in which cAMP activates ERK, inhibition of PKA and Ras, but not Rap1, abolished cAMP-mediated ERK activation. We conclude that cAMP-induced regulation of ERK and activation of Rap1 are independent processes.

713 citations


Journal ArticleDOI
TL;DR: It is recommended to use the lowest intraabdominal pressure allowing adequate exposure of the operative field, rather than using a routine pressure, and abdominal wall lifting combined with low-pressure pneumoperitoneum might be an alternative.
Abstract: Background: The pneumoperitoneum is the crucial element in laparoscopic surgery. Different clinical problems are associated with this procedure, which has led to various modifications of the technique. The aim of this guideline is to define the scientifically proven standards of the pneumoperitoneum. Methods: Based on systematic literature searches (Medline, Embase, and Cochrane), an expert panel consensually formulated clinical recommendations, which were graded according to the strength of available literature evidence. Recommendations: Preoperatively, all patients should be assessed for the presence of cardiac, pulmonary, hepatic, renal, or vascular comorbidity. Presupposing appropriate perioperative measures and surgical technique, there is no reason to contraindicate pneumoperitoneum in patients with peritonitis or intraabdominal malignancy. During laparoscopy, monitoring of end tidal CO2 concentration is mandatory. The available data on closed- (Veress needle) and open-access techniques do not allow us to principally favor the use of either technique. Using 2 to 5-mm instead of 5 to 10-mm trocars improves cosmetic result and postoperative pain marginally. It is recommended to use the lowest intraabdominal pressure allowing adequate exposure of the operative field, rather than using a routine pressure. In patients with limited cardiac, pulmonary, or renal function, abdominal wall lifting combined with low-pressure pneumoperitoneum might be an alternative. Abdominal wall lifting devices have no clinically relevant advantages compared to low-pressure (5–7 mmHg) pneumoperitoneum. In patients with cardiopulmonary diseases, intra- and postoperative arterial blood gas monitoring is recommended. The clinical benefits of warmed, humidified insufflation gas are minor and contradictory. Intraoperative sequential intermittent pneumatic compression of the lower extremities is recommended for all prolonged laparoscopic procedures. For the prevention of postoperative pain a wide range of treatment options exists. Although all these options seem to reduce pain, the data currently do not justify a general recommendation.

Journal ArticleDOI
TL;DR: Recent literature showing the involvement of BDNF/TrkB signaling in hippocampal-dependent learning paradigms, as well as in the types of cellular plasticity proposed to underlie learning and memory are reviewed.
Abstract: One of the most rigorously investigated problems in modern neuroscience is to decipher the mechanisms by which experience-induced changes in the central nervous system are translated into behavioral acquisition, consolidation, retention, and subsequent recall of information. Brain-derived neurotrophic factor (BDNF) has recently emerged as one of the most potent molecular mediators of not only central synaptic plasticity, but also behavioral interactions between an organism and its environment. Recent experimental evidence indicates that BDNF modulates synaptic transmission and plasticity by acting across different spatial and temporal domains. BDNF signaling evokes both short- and long-term periods of enhanced synaptic physiology in both pre- and postsynaptic compartments of central synapses. Specifically, BDNF/TrkB signaling converges on the MAP kinase pathway to enhance excitatory synaptic transmission in vivo, as well as hippocampal-dependent learning in behaving animals. Emerging concepts of the intracellular signaling cascades involved in synaptic plasticity induced through environmental interactions resulting in behavioral learning further support the contention that BDNF/TrkB signaling plays a fundamental role in mediating enduring changes in central synaptic structure and function. Here we review recent literature showing the involvement of BDNF/TrkB signaling in hippocampal-dependent learning paradigms, as well as in the types of cellular plasticity proposed to underlie learning and memory.

Journal ArticleDOI
Jon A. Hardie1, A S Buist1, W M Vollmer1, Ivar Ellingsen1, Per Bakke1, Odd Mørkve1 
TL;DR: The authors examined the extent of COPD misdiagnosis using this definition in healthy, never-smoker, asymptomatic adults aged >70 yrs in Bergen, Norway and found that the criteria used to define the various stages of chronic obstructive pulmonary disease need to be age-specific.
Abstract: The Global Initiative for Chronic Obstructive Lung Disease (GOLD) has defined stage I chronic obstructive pulmonary disease (COPD) as forced expiratory volume in one second/forced vital capacity (FEV1/FVC)% 80%. Stage 2 has been defined as FEV1/FVC 70 yrs in Bergen, Norway. A respiratory questionnaire was mailed to a random sample of 2,871 persons aged >70 yrs. In a random, well-defined subgroup of 208 never-smoker respondents with no current respiratory disease and significant dyspnoea or heart disease/hypertension complicated with dyspnoea, 71 were able to perform an acceptable spirometry. Approximately 35% of these healthy, elderly never-smokers had an FEV1/FVC% of 80 yrs approximately 50% would be classified as having COPD and approximately one-third would have an FEV1 of 70 yrs. The criteria used to define the various stages of chronic obstructive pulmonary disease need to be age-specific.

Journal ArticleDOI
TL;DR: Although the particular taxonomic composition of microbial communities inhabiting a multipond solar saltern could vary among protocols, the general structure of the microbial assemblages was maintained.
Abstract: Summary Microbial communities inhabiting a multipond solar saltern were analysed and compared using SSU rRNA polymerase chain reaction (PCR)-based fingerprintings carried out in parallel by four laboratories. A salinity gradient from seawater (3.7%) to NaCl precipitation (37%) was studied for Bacteria, Archaea and Eukarya, and laboratories applied their own techniques and protocols on the same set of samples. Members of all three domains were retrieved from all salt concentrations. Three fingerprinting techniques were used: denaturing gradient gel electrophoresis (DGGE), ribosomal internal spacer analysis (RISA), and terminal-restriction fragments length polymorphism (T-RFLP). In addition, each laboratory used its own biomass collection method and DNA extraction protocols. Prokaryotes were addressed using DGGE and RISA with different ‘domain-specific’ primers sets. Eukaryotes were analysed by one laboratory using DGGE and T-RFLP, but targeting the same 18S rDNA site. Fingerprints were compared through cluster analysis and non-metric multidimensional scaling plots. This exercise allowed fast comparison of microbial assemblages and determined to what extent the picture provided by each laboratory was similar to those of others. Formation of two main, salinity-based groups of samples in prokaryotes (4–15% and 22–37% salinity) was consistent for all the laboratories. When other clusters appeared, this was a result of the particular technique and the protocol used in each case, but more affected by the primers set used. Eukaryotic microorganisms changed more from pond to pond; 4–5% and 8–37% salinity were but the two main groups detected. Archaea showed the lowest number of bands whereas Eukarya showed the highest number of operational taxonomic units (OTUs) in the initial ponds. Artefacts appeared in the DGGE from ponds with extremely low microbial richness. On the other hand, different 16S rDNA fragments with the same restriction or internal transcribed spacer (ITS) length were the main limitations for T-RFLP and RISA analyses, respectively, in ponds with the highest OTUs richness. However, although the particular taxonomic composition could vary among protocols, the general structure of the microbial assemblages was maintained.

Journal ArticleDOI
TL;DR: Robust pathways examined in afferents to the ventrolateral preoptic nucleus (VLPO) suggest candidate mechanisms by which sleep may be influenced by brain systems regulating arousal, autonomic, limbic, and circadian functions.
Abstract: Sleep is influenced by diverse factors such as circadian time, affective states, ambient temperature, pain, etc., but pathways mediating these influences are unknown. To identify pathways that may influence sleep, we examined afferents to the ventrolateral preoptic nucleus (VLPO), an area critically implicated in promoting sleep. Injections of the retrograde tracer cholera toxin B subunit (CTB) into the VLPO produced modest numbers of CTB-labeled monoaminergic neurons in the tuberomammillary nucleus, raphe nuclei, and ventrolateral medulla, as well as a few neurons in the locus coeruleus. Immunohistochemistry for monoaminergic markers showed dense innervation of the VLPO by histaminergic, noradrenergic, and serotonergic fibers. Along with previous findings, these results suggest that the VLPO and monoaminergic nuclei may be reciprocally connected. Retrograde and anterograde tracing showed moderate or heavy inputs to the VLPO from hypothalamic regions including the median preoptic nucleus, lateral hypothalamic area, and dorsomedial hypothalamic nucleus (DMH), autonomic regions including the infralimbic cortex and parabrachial nucleus, and limbic regions including the lateral septal nucleus and ventral subiculum. Light to moderate inputs arose from orexin and melanin concentrating hormone neurons, but cholinergic or dopaminergic inputs were extremely sparse. Suprachiasmatic nucleus (SCN) projections to the VLPO were sparse, but the heavy input to the VLPO from the DMH, which receives direct and indirect SCN inputs, could provide an alternate pathway regulating the circadian timing of sleep. These robust pathways suggest candidate mechanisms by which sleep may be influenced by brain systems regulating arousal, autonomic, limbic, and circadian functions.

Journal ArticleDOI
TL;DR: It is demonstrated that all three factors in combination may explain the observed pattern in species richness in the Nepalese Himalayas, including hard boundaries, an assumed linear relationship between species richness and altitude, and the effect of interpolation when incomplete sampling is assumed.
Abstract: We compare different null models for species richness patterns in the Nepalese Himalayas, the largest altitudinal gradient in the world. Species richness is estimated by interpolation of presences between the extreme recorded altitudinal ranges. The number of species in 100-m altitudinal bands increases steeply with altitude until 1,500 m above sea level. Between 1,500 and 2,500 m, little change in the number of species is observed, but above this altitude, a decrease in species richness is evident. We simulate different null models to investigate the effect of hard boundaries and an assumed linear relationship between species richness and altitude. We also stimulate the effect of interpolation when incomplete sampling is assumed. Some modifications on earlier simulations are presented. We demonstrate that all three factors in combination may explain the observed pattern in species richness. Estimating species richness by interpolating species presence between maximum and minimum altitudes creates an artificially steep decrease in species richness toward the ends of the gradient. The addition of hard boundaries and an underlying linear trend in species richness is needed to simulate the observed broad pattern in species richness along altitude in the Nepalese Himalayas.

Journal ArticleDOI
TL;DR: The protective effect of previous pregnancy against preeclampsia is transient and after adjustment for the interval between births, a change of partner is not associated with an increased risk of preeClampsia.
Abstract: Background The risk of preeclampsia is generally lower in second pregnancies than in first pregnancies, but not if the mother has a new partner for the second pregnancy. One explanation is that the...

Journal ArticleDOI
TL;DR: Though not directly related to reported exposure to bullying behaviors, generalized self-efficacy seemed to act as a moderator of the relationship between exposure tobullying behaviors and psychological health complaints.
Abstract: The aim of this study was to investigate the relationships between exposure to behaviors identified as workplace bullying and self-report measurements of psychological and psychosomatic health complaints. Secondly, we investigated whether these relationships were mediated by the state negative affectivity of the victim. Thirdly, we investigated the extent to which generalized self-efficacy moderated the relationships between exposure to bullying behaviors and health complaints. Two hundred and twenty-four white- and blue-collar employees from a Danish manufacturing company participated in the study. Exposure to bullying behaviors was associated with an increase in psychological health complaints, increased levels of psychosomatic complaints and an elevated level of state negative affectivity. Whereas bullying by itself accounted for 27% of the variance in psychological health complaints and 10% of the variance in psychosomatic complaints, the results pointed to state negative affectivity as a partial mediator of the relationships between exposure to bullying behaviors and both measures of self-reported health. Though not directly related to reported exposure to bullying behaviors, generalized self-efficacy seemed to act as a moderator of the relationship between exposure to bullying behaviors and psychological health complaints.

Journal ArticleDOI
TL;DR: High–resolution palaeolimnological data are presented, which show that increases in phytoplankton production developed from the 1930s onwards, which parallels human–population growth and agricultural activity in the Lake Victoria drainage basin.
Abstract: Lake Victoria, the largest tropical lake in the world, suffers from severe eutrophication and the probable extinction of up to half of its 500+ species of endemic cichlid fishes. The continuing degradation of Lake Victoria's ecological functions has serious long-term consequences for the ecosystem services it provides, and may threaten social welfare in the countries bordering its shores. Evaluation of recent ecological changes in the context of aquatic food-web alterations, catchment disturbance and natural ecosystem variability has been hampered by the scarcity of historical monitoring data. Here, we present high-resolution palaeolimnological data, which show that increases in phytoplankton production developed from the 1930s onwards, which parallels human-population growth and agricultural activity in the Lake Victoria drainage basin. Dominance of bloom-forming cyanobacteria since the late 1980s coincided with a relative decline in diatom growth, which can be attributed to the seasonal depletion of dissolved silica resulting from 50 years of enhanced diatom growth and burial. Eutrophication-induced loss of deep-water oxygen started in the early 1960s, and may have contributed to the 1980s collapse of indigenous fish stocks by eliminating suitable habitat for certain deep-water cichlids. Conservation of Lake Victoria as a functioning ecosystem is contingent upon large-scale implementation of improved land-use practices.

Journal ArticleDOI
TL;DR: The results reject the idea of corresponding maxima in endemic species and species richness in the lowlands tentatively deduced from Stevens’ elevational Rapoport effect, but hard-boundaries should be viewed as dynamic rather than static when broad-scale biogeographical patterns with a historical component are being interpreted.
Abstract: Aim Species richness and endemic richness vary along elevation gradients, but not necessarily in the same way. This study tests if the maxima in gamma diversity for flowering plants and the endemic subset of these plants are coherent or not. Location The study was conducted in Nepal, between 1000 and 5000 m a.s.l. Methods We used published data on distribution and elevational ranges of the Nepalese flora to interpolate presence between maximum and minimum elevations. Correlation, regression and graphical analyses were used to evaluate the diversity pattern between 1000 and 5000 m a.s.l. Results The interval of maximum species endemic to Nepal or the Himalayas (3800‐4200 m) is above the interval of maximum richness (1500‐2500 m). The exact location of maximum species density is uncertain and its accuracy depends on ecologically sound estimates of area in the elevation zones. There is no positive statistically significant correlation between log-area and richness (total or endemic). Total richness is positively correlated with log-area-adjusted, i.e. estimated area adjusted for the degree of topographic heterogeneity. The proportion of endemic species increases steadily from low to high elevations. The peak in endemism (c. 4000 m) corresponds to the start of a rapid decrease in species richness above 4000 m. This may relate to the last glacial maximum (equilibrium line at c. 4000 m) that penetrated down to 2500‐3000 m. This dynamic hard boundary may have caused an increase in the extinction rate above 4000 m, and enhanced the probability of isolation and facilitated speciation of neoendemics, especially among genera with a high proportion of polyploids. Main conclusions The results reject the idea of corresponding maxima in endemic species and species richness in the lowlands tentatively deduced from Stevens’ elevational Rapoport effect. They confirm predictions based on hard boundary theory, but hard-boundaries should be viewed as dynamic rather than static when broad-scale biogeographical patterns with a historical component are being interpreted.

Journal ArticleDOI
TL;DR: Turbidity has both positive and negative effects on prey detection, by increasing or diminishing the contrast between prey and background due to the scattering of light, and might have a structuring effect on a fish community.
Abstract: Turbidity has both positive and negative effects on prey detection, by increasing or diminishing the contrast between prey and background due to the scattering of light. The positive effect of turbidity on prey contrast depends on the optical properties, scattering properties of suspended particles and the visual sensitivity of the predator. The positive effect of turbidity is pronounced for larval fish, given that their visual field is short, leaving fewer particles between them and their prey to scatter light and interfere with detection. This relationship, together with a decreased risk of predation, makes turbid environments more optimal for some species and size groups of fish (planktivores and fish larvae) and less so for others (adult piscivore fish). Thus, turbidity might have a structuring effect on a fish community. Recently it has been demonstrated that UV light might have positive effects on prey detection and consumption. How UV light might interact with different kinds of particles producing...

Journal ArticleDOI
TL;DR: The authors consider the relationship between party institutionalization and party system institutionalization, pointing out that they are not necessarily convergent and propose an analytic model to evaluate the convergence of the two models.
Abstract: The literature on democratisation emphasises the contribution of political parties, and in that context the importance of party institutionalization. But this concept remains relatively unexplored. Our article first considers the relationship between party institutionalization and party system institutionalization, pointing out that they are not necessarily convergent. We then review the existing literature on party institutionalization, indicating weaknesses and contradictions, before offering our own analytic model. In the final section we identify some of the key considerations arising when this model is applied to the particular circumstances of democratic transition in the Third World.


Journal ArticleDOI
TL;DR: A review of these experiments shows that the coefficient arising in the theoretical analysis can be estimated from the reported data as mentioned in this paper, and recently developed pore-scale models that simulate interface dynamics within a network of pores can also be used to estimate the appropriate dynamic coefficients.
Abstract: Capillary pressure plays a central role in the description of water flow in unsaturated soils. While capillarity is ubiquitous in unsaturated analyses, the theoretical basis and practical implications of capillarity in soils remain poorly understood. In most traditional treatments of capillary pressure, it is defined as the difference between pressures of phases, in this case air and water, and is assumed to be a function of saturation. Recent theories have indicated that capillary pressure should be given a more general thermodynamic definition, and its functional dependence should be generalized to include dynamic effects. Experimental evidence has slowly accumulated in the past decades to support a more general description of capillary pressure that includes dynamic effects. A review of these experiments shows that the coefficient arising in the theoretical analysis can be estimated from the reported data. The calculated values range from 10 4 to 10 7 kg (m s) −1 . In addition, recently developed pore-scale models that simulate interface dynamics within a network of pores can also be used to estimate the appropriate dynamic coefficients. Analyses of experiments reported in the literature, and of simulations based on pore-scale models, indicate a range of dynamic coefficients that spans about three orders of magnitude. To examine whether these coefficients have any practical effects on larger-scale problems, continuum-scale simulators may be constructed in which the dynamic effects are included. These simulators may then be run to determine the range of coefficients for which discernable effects occur. Results from such simulations indicate that measured values of dynamic coefficients are within one order of magnitude of those values that produce significant effects in field simulations. This indicates that dynamic effects may be important for some field situations, and numerical simulators for unsaturated flow should generally include the additional term(s) associated with dynamic capillary pressure.

Journal ArticleDOI
TL;DR: A role for BDNF in triggering transcription-dependent, late phase LTP in the intact adult brain is supported and is associated with enhancement in both synaptic strength and granule cell excitability (EPSP–spike coupling).
Abstract: Acute intrahippocampal infusion of brain-derived neurotrophic factor (BDNF) leads to long-term potentiation (BDNF-LTP) of synaptic transmission at medial perforant path-->granule cell synapses in the rat dentate gyrus. Endogenous BDNF is implicated in the maintenance of high-frequency stimulation-induced LTP (HFS-LTP). However, the relationship between exogenous BDNF-LTP and HFS-LTP is unclear. First, we found that BDNF-LTP, like HFS-LTP, is associated with enhancement in both synaptic strength and granule cell excitability (EPSP-spike coupling). Second, treatment with a competitive NMDA receptor (NMDAR) antagonist blocked HFS-LTP but had no effect on the development or magnitude of BDNF-LTP. Thus, NMDAR activation is not required for the induction or expression of BDNF-LTP. Formation of stable, late phase HFS-LTP requires mRNA synthesis and is coupled to upregulation of the immediate early gene activity-regulated cytoskeleton-associated protein (Arc). Local infusion of the transcription inhibitor actinomycin D (ACD) 1 hr before or immediately before BDNF infusion inhibited BDNF-LTP and upregulation of Arc protein expression. ACD applied 2 hr after BDNF infusion had no effect, defining a critical time window of transcription-dependent synaptic strengthening. Finally, the functional role of BDNF-LTP was assessed in occlusion experiments with HFS-LTP. HFS-LTP was induced, and BDNF was infused at time points corresponding to early phase (1 hr) or late phase (4 hr) HFS-LTP. BDNF applied during the early phase led to normal BDNF-LTP. In contrast, BDNF-LTP was completely occluded during the late phase. The results strongly support a role for BDNF in triggering transcription-dependent, late phase LTP in the intact adult brain.

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TL;DR: Water samples from eight ponds were analysed, covering a salinity range from near sea water to saturated sodium chloride, and both Bacteria and Archaea showed the same pattern; as salinity increased, the number of different clusters decreased, and only one cluster became dominant.
Abstract: Bacterial and archaeal assemblages have been studied in a multipond solar saltern using a range of microbial ecology techniques by four laboratories simultaneously. These include 16S rDNA sequencing from both denaturing gradient gel electrophoresis (DGGE) and clone libraries, and culturing methods. Water samples from eight ponds were analysed, covering a salinity range from near sea water (4% salt) to saturated sodium chloride (37% salt; ponds called crystallizers). Clone libraries focused on ponds with salinity of 8%, 22% and 32%. Although different cloning strategies were able to retrieve the same type of dominant sequences, there were differing degrees of success with less abundant sequences. Thus, the use of two sets of primers recovered a higher number of phylotypes. Bacterial and archaeal isolates were, however, different from any of the retrieved environmental sequences. For Bacteria, most sequences in the 8% salt pond were related to organisms of marine origin. Thus, representatives of the alpha-, beta-, gamma- and epsilon-subdivisions of Proteobacteria, the Cytophaga-Flavobacterium-Bacteroides group (CFB), high-G+C Gram-positive bacteria and cyanobacteria were found. In the 22% salt pond, alpha- and gamma-Proteobacteria, cyanobacteria and CFB were the only groups found, and most of them were related to specialized halophilic bacteria. From the 32% salt pond, only CFB were found, and most of the sequences retrieved clustered with Salinibacter ruber, an extremely halophilic bacterium. A decrease in the richness of bacterial genera was therefore apparent along the gradient. Archaea behaved quite similarly. In the lowest salinity ponds, sequences were related to environmental clones of Marine Archaea Group III (Thermoplasmales relatives) and to unclassified branches of Euryarchaeaota. In the 8%, 22% and 32% ponds, most of the clones were related to different cultured strains of Halobacteriaceae. Finally, most sequences from the crystallizers clustered with the uncultured square archaeon SPhT. Crenarchaeaota were not detected. Despite the fact that higher prokaryotic richness was apparent in the lower salinity ponds than in the crystallizers, the diversity index from clone libraries calculated according to Shannon and Weaver did not show this trend. This was because diversity in the crystallizers can be considered as 'microdiversity', the co-existence of several closely related clones of Bacteria (the S. ruber cluster) and Archaea (the SPhT cluster). Regardless of the changes in abundance, both Bacteria and Archaea showed the same pattern; as salinity increased, the number of different clusters decreased, and only one cluster became dominant. Both clusters, however, showed a considerable degree of microdiversity. The meaning of such microdiversity remains to be determined.

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TL;DR: The results show that different growth conditions and differences in the bacterial community may explain some of the variability of previously reported elemental and carbon-volume ratios.
Abstract: Marine bacterioplankton were isolated and grown in batch cultures until their growth became limited by organic carbon (C), nitrogen (N), or phosphorus (P). Samples were taken from the cultures at b ...

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TL;DR: Serotonergic activity may be accompanied by waking or sleep depending on the brain area and receptor type involved in the response, on the current behavioural state and on the concomitant agonism/antagonism of other neurotransmitter systems.

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TL;DR: Results provide the first in situ dissection of GvH effects by mHag-specific CTLs and show that ubiquitously expressed mHags are the prime targets of GVH disease.
Abstract: Minor histocompatibility antigens (mHags) are immunogenic peptides from polymorphic cellular proteins that induce strong T-cell responses after human leukocyte antigen (HLA)-matched, mHag-mismatched stem-cell transplantation. mHags with broad or limited tissue expression are target antigens for graft-versus-host (GvH) and graft-versus-leukemia (GvL) reactivities. Separation of these activities is crucial for adoptive immunotherapy of leukemia without GvH disease. Therefore, using a skin-explant assay we investigated the in situ activities of cytotoxic T lymphocytes (CTLs) specific for the ubiquitously expressed mHag H-Y and for the hematopoietic-restricted mHags HA-1 and HA-2. H-Y-specific CTLs, visualized by tetrameric HLA-mHag peptide complexes, infiltrated male skin sections within 24 hours, induced severe GvH reactions of grade III-IV and produced high levels of IFN-gamma. In contrast, CTLs specific for the hematopoietic system-specific mHags HA-1 and HA-2 induced no or low GvH reactions above background and produced little or no interferon-gamma, unless the skin sections were preincubated with HA-1/HA-2 synthetic peptides. These results provide the first in situ dissection of GvH effects by mHag-specific CTLs and show that ubiquitously expressed mHags are the prime targets of GvH disease.

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TL;DR: In this article, a real-time mass bias correction is made by aspirating a Tl/U tracer at the same time as laser ablation, which is similar to that described in Horn et al. (2000), except that enriched 233U rather than 235U is used in the tracer solution Correction for laser-induced Pb/U elemental fractionation is based on a mathematical treatment of time-resolved data that is independent of laser-ablation characteristics.