Many pathways of invasion have been posited, but ecologists lack an experimental framework to identify which mechanisms are dominant in a given invasion scenario. Plant-soil feedbacks (PSFs) are one such mechanism that tend to initially facilitate, but over time attenuate, invasive species' impacts on plant diversity and ecosystem function. PSFs are typically measured under greenhouse conditions and are often assumed to have significant effects under field conditions that change over time.
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November 2023
Predicting plastic responses is crucial to assess plant species potential to adapt to climate change, but little is known about which factors drive the biogeographical patterns of phenotypic plasticity in plants. Theory predicts that climatic variability would select for increased phenotypic plasticity, whereas evidence indicates that stressful conditions can limit phenotypic plasticity. Using a meta-analytic, phylogeny-corrected approach to global data on plant phenotypic plasticity, we tested whether latitude, climate, climatic variability and/or stressful conditions are predictors of plastic responses at a biogeographical scale.
View Article and Find Full Text PDFInvasive species can alter the structure and function of the communities they invade, as well as lead to biotic homogenization across their invasive range, thus affecting large-scale diversity patterns. The mechanisms by which invasive species can lead to biotic homogenization are poorly understood. We argue that invasive species acting as strong, deterministic, and consistent filters within and across invaded communities are likely to cause biotic homogenization at multiple spatial scales.
View Article and Find Full Text PDFInvasive species dominance in invaded communities may not be long-lasting due to regulatory processes, such as plant-soil feedbacks and neighboring species adaptation. Further, the change in species competitive ability may be contingent upon neighbor identity (i.e.
View Article and Find Full Text PDFRiegler, M, Stotz, G, Fitzgerald, K, Munoz, CK, Lewis, J, Ring, S, and Astorino, TA. Acute responses to the 7-minute workout. J Strength Cond Res 31(9): 2572-2578, 2017-A popular smartphone application called the 7-Minute Workout (7Min) claims to be scientifically proven to promote weight loss and improve cardiovascular function.
View Article and Find Full Text PDFBackground And Aims: Disturbance often drives plant invasion and may modify community assembly. However, little is known about how these modifications of community patterns occur in terms of taxonomic, functional and phylogenetic structure. This study evaluated in an arid shrubland the influence of disturbance by an endemic rodent on community functional divergence and phylogenetic structure as well as on plant invasion.
View Article and Find Full Text PDFInvasive plant species can have a strong negative impact on the resident native species, likely imposing new selective pressures on them. Altered selective pressures may result in evolutionary changes in some native species, reducing competitive exclusion and allowing for coexistence with the invader. Native genotypes that are able to coexist with strong invaders may represent a valuable resource for management efforts.
View Article and Find Full Text PDFTredennick et al. criticize one of our statistical analyses and emphasize the low explanatory power of models relating productivity to diversity. These criticisms do not detract from our key findings, including evidence consistent with the unimodal constraint relationship predicted by the humped-back model and evidence of scale sensitivities in the form and strength of the relationship.
View Article and Find Full Text PDFThe search for predictions of species diversity across environmental gradients has challenged ecologists for decades. The humped-back model (HBM) suggests that plant diversity peaks at intermediate productivity; at low productivity few species can tolerate the environmental stresses, and at high productivity a few highly competitive species dominate. Over time the HBM has become increasingly controversial, and recent studies claim to have refuted it.
View Article and Find Full Text PDFSpatial variation in host plant availability may lead to specialization in host use and local host adaptation in herbivorous insects, which may involve a cost in performance on other hosts. We studied two geographically separated populations of the seed beetle Megacerus eulophus (Coleoptera: Bruchidae) in central Chile: a population from the host Convolvulus chilensis (in Aucó) and a population from C. bonariensis (in Algarrobo).
View Article and Find Full Text PDFHigh-elevation ecosystems are traditionally viewed as environments in which predominantly autogamous breeding systems should be selected because of the limited pollinator availability. Chaetanthera renifolia (Asteraceae) is an endemic monocarpic triennial herb restricted to a narrow altitudinal range within the high Andes of central Chile (3300-3500 m a.s.
View Article and Find Full Text PDFChronic diffuse liver diseases produce a characteristic ultrasound image called bright liver. On the basis of liver attenuation, two major appearances can be observed: low and high attenuation types. It is proved that high attenuation is associated with fatty liver and subcutaneous fat thickness correlates with attenuation.
View Article and Find Full Text PDFUnlabelled: The first choice, and the most efficient therapy for chronic hepatitis C is the pegylated interferon + ribavirin treatment. The introduction and application of the STOP rule (pegylated interferon + ribavirin treatment should be stopped in cases without sufficient virological answer for the therapy at the 12th or 24th week of the treatment) is motivated by the very high cost of this treatment.
Aims: The greatest problem of the application of the STOP rule is that these patients are not coming in for the proven advantages of one-year interferon treatment (arrest or decrease the inflammation, decrease or prevent the progression to liver cirrhosis, decrease probability or prevent the development of hepatocellular carcinoma), which were observed almost in virologically slow-, partial-, or non-responder patients who received one-year interferon therapy.
Introduction: 239 anti-HCV seropositive blood donors (132 male, 107 female, age: 19-61, mean: 40.59 y.) and 174 family members of them (74 male, 100 female, age: 4-65, mean: 23.
View Article and Find Full Text PDFEur J Gastroenterol Hepatol
May 2001
Objective: Chronic hepatitis is characterized by necrosis of liver cells, accompanied by an inflammatory reaction and compensatory cell proliferation. The interaction of the core and non-structural proteins of hepatitis C virus (HCV) with several cellular factors suggests that cell proliferation may be influenced by HCV. The aim of this study was to investigate hepatocyte proliferation and DNA ploidy patterns in patients with chronic viral hepatitis C (CH-C) compared with chronic non-viral hepatitis (CH-N), using a TV image analysis method.
View Article and Find Full Text PDFBackground: The rare cases of patients with 48-hour ultrarapid cycling allow close investigation of mood cycles in affective disorders, because rhythmic changes in psychopathologic state and biological parameters happen very precisely.
Method: A 67-year-old white man who had experienced bipolar 48-hour ultrarapid cycling (DSM-IV 296.80) for several years was studied without any medication and then again studied 4 weeks later during treatment with valproate (1800 mg/day).
Rationale: A serotonergic dysfunction is supposed to play a pathogenetic role in depression, but there is a considerable number of non-responders in the acute treatment of depression with serotonergic agents like SSRI. Thus, an indicator of central serotonergic activity could lead to a more specific pharmacological treatment of depression. In animal and human data there is a growing amount of evidence that a strong loudness dependency of late auditory evoked potentials (LDAEP) is an indicator of low serotonergic activity and vice versa.
View Article and Find Full Text PDFThe use of psychostimulants as an adjuvant therapy in treatment-resistant depression is not very common nowadays and has been the subject of much criticism. This article gives a brief review of the literature and reports on the findings from a retrospective study carried out in 65 depressed patients treated with psychostimulants (amphetamine and methylphenidate) in addition to conventional antidepressants. Thirty-eight out of 65 patients showed significant improvement, in particular with respect to energy mood, and psychomotor activity.
View Article and Find Full Text PDFThe term of telepathology can be determined as diagnostic work of the pathologist at distance via an interactive telecommunication connection in which the image of the specimen appears on a monitor instead of viewing it directly through a microscope. Being a part of the telemedicine, the fast development of the telepathology is based on the revolution of the new digital technology. Technical advances of telecommunication and of image procession in the latest 80s have provided the means to transfer huge amount of visual information in narrow communication bandwidth in two direction link.
View Article and Find Full Text PDFAuthors have investigated the hepatitis B and D virus antigens in the liver tissue of 30 HBsAg and/or anti-HD seropositive patients (23 males, 7 females, age: 20-65, mean: 44 years) by immunohistochemical method. The immunohistochemical identification of HBsAg, HBcAg and HDAg in 42 liver sample (36 obtained by percutaneous biopsy, 6 from dissection) of 30 patients was performed with Dako and Sorin Biomedica kits. The detailed virus serologic examinations were carried out with Biomedica and Abbott kits by radioimmunoassay and ELISA methods.
View Article and Find Full Text PDFThe results of 43 interferon treatments of 35 patients (23 male, 12 female) are reported. The duration of the treatment was 6-18 months, the dose of interferon was 3x3-5 MU weekly. Complete response (HCV RNA became negative) was found in 11, relapse was observed in 3 patients.
View Article and Find Full Text PDFThyroid imaging was performed using technetium-99m methoxyisobutylisonitrile and technetium-99m pertechnetate in 58 patients. The 99mTc-pertechnetate scans showed a total of 77 nodules: 60 cold, 13 hot and 4 of normal activity. There was no 99mTc-MIBI accumulation in 46.
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