Allometric Models for Tree Volume and Total Aboveground Biomass in a Tropical Humid Forest in Costa Rica1

Allometric equations for the estimation of tree volume and aboveground biomass in a tropical humid forest were developed based on direct measurements of 19 individuals of seven tree species in Northern Costa Rica. The volume and the biomass of the stems represented about two‐thirds of the total volume and total aboveground biomass, respectively. The average stem volume varied between 4 and 11 Mg/tree and the average total aboveground biomass ranged from 4 to 10 mg/tree. The mean specific gravity of the sampled trees was 0.62 ± 0.06 (g/cm³). The average biomass expansion factor was 1.6 ± 0.2. The best‐fit equations for stem and total volume were of logarithmic form, with diameter at breast height (R²= 0.66 ? 0.81) as an independent variable. The best‐fit equations for total aboveground biomass that were based on combinations of diameter at breast height, and total and commercial height as independent variables had R² values between 0.77 and 0.87. Models recommended for estimating total aboveground biomass are based on diameter at breast height, because the simplicity of these models is advantageous. This variable is easy to measure accurately in the field and is the most common variable recorded in forest inventories. Two widely used models in literature tend to underestimate aboveground biomass in large trees. In contrast, the models developed in this study accurately estimate the total aboveground biomass in these trees.     

Platelet dysfunction as the presenting feature of atypical myelodysplastic syndrome with monosomy 7, normal blood counts and no bleeding tendency

A 71-year-old male patient with atypical myelodysplastic syndrome showing monosomy 7 is described. He presented with severe foot pains, trophic skin and nail changes, loss of distal pulses, all compatible with peripheral arterial occlusive disease. He had completely normal blood counts and no bleeding tendency. Prolonged bleeding time was disclosed by chance, during routine haemostatic studies. An acquired platelet dysfunction was considered, with prolonged bleeding time and large platelets that failed to aggregate in response to arachidonic acid and that had impaired response to collagen and adrenaline. The bone marrow was hypercellular, with numerous dysplastic megakaryocytes and two other slightly dysplastic myeloid lines. Cytogenetic analyses of the bone marrow cells showed a mosaic karyotype: 46,XY/45,XY,-7. On angiography, bilateral thrombosis of the iliac, superficial femoral and popliteal arteries was disclosed. The patient was prepared with platelet transfusions. Arterial thrombectomy and amputation of the left calf were performed. Ten months later, his blood counts showed mild pancytopenia. He died at home. The authors discuss some clinical and pathogenetical aspects of such presentations of myelodysplastic syndromes.     

Empathy and Effortful Control Effects on Early Adolescents’ Aggression: When Do Students’ Perceptions of Their School Climate Matter?

Guided by the social emotional learning framework, this study examined whether early adolescents’ social awareness (empathic concern, perspective taking) and self-management (effortful control) would uniquely contribute to early adolescents’ subsequent forms of aggression, and whether perceptions of their school climate (friction, cohesion, competition, satisfaction with classes) would moderate those associations. Participants were 479 10- to 14-year old students (54% female; 78% European American) who completed the first wave of a survey in sixth and seventh grades and the second wave 1 year later. Hierarchical regression analyses indicated that across gender, empathic concern was the only competency to reduce subsequent overt and relational aggression. None of the school climate perceptions made unique contributions to aggression, nor did they show protective functions. Rather, several instances of cumulative advantage were observed, whereby positive school climate perceptions only reduced aggression for students with high levels of empathic concern. Unexpectedly, boys’ perceived cohesion contributed to overt aggression if they reported high levels of effortful control.     

Do the seeds of <Emphasis Type="Italic">Solidago gigantea</Emphasis> Aiton have physiological determinants of invasiveness?

Solidago gigantea Ait. (goldenrod) belongs to the most expansive environmental weeds, and it is the most dangerous plant-invader of American origin in Europe. The species easily propagates vegetatively, but it also produces large amounts of wind-disseminated achenes that contribute to the colonization of new areas. A sound knowledge of the germination biology of goldenrods is required to control the spread of this invasive species. The objective of this study was to investigate selected aspects of germination of giant goldenrod achenes and to determine: the influence of temperature and humidity on seed dormancy and germination, the content of soluble carbohydrates in seeds and the sensitivity of seeds to selected phytohormones. Unlike native weed species of the same family, S. gigantea seeds did not display symptoms of innate dormancy, and high seed vigor was maintained after storage in a wide range of temperatures, in both dry and moist conditions. The physiological mechanisms behind those traits have not yet been fully explored, but they could be associated with the relatively high sucrose-to-hexose ratio in seeds and significant sensitivity to abscisic acid. More extensive research is required to explain the internal causes for the atypical behavior of goldenrod seeds during dry and moist storage, especially in the context of its invasiveness, because the species has a preference for sites located close to river banks.     

Determination of new 2,3-benzodiazepines in rat plasma using high-performance liquid chromatography with ultraviolet detection

A method for the analysis of [1-(4-aminophenyl)-3,5-dihydro-7,8-dimethoxy-4H-2,3-benzodiazepin-4-one] (CFM-2) and its analogues CFM-3, CFM-4 and CFM-5 in rat plasma was developed. The 2,3-benzodiazepines (2,3-BZs) were extracted by liquid–liquid extraction and analyzed using high-performance liquid chromatography (HPLC) with ultraviolet detection (UV) at 240 nm. The method exhibited a large linear range from 0.05 to 2 μg/ml with an intra-assay accuracy for all studied compounds ranging from 92 to 105.5%; whereas the intra-assay precision ranged from 0.59 to 8.16% in rat plasma. The inter-assay accuracy of CFM-2, CFM-4 and their 3-methyl derivatives, CFM-3 and CFM-5 ranged from 92.2 to 107% and the inter-assay precision ranged from 2.17 to 11.9% in rat plasma. The lower limit of detection was 5.5 ng/ml for CFM-2, 6.5 ng/ml for CFM-3, 7 ng/ml for CFM-4 and 8.5 ng/ml for CFM-5 in rat plasma. The pharmacokinetic study demonstrated that 2,3-BZs achieved a peak plasma concentration between 45 and 75 min after drug administration. Moreover, we observed that plasma chromatograms of rats treated with CFM-3, CFM-4 and CFM-5, respectively, showed a peak consistent with CFM-2. Our study suggests that CFM-4, CFM-5 and CFM-3 are prodrugs of CFM-2, in which they are biotransformed in vivo via different metabolic pathways. In particular, CFM-2 has been proven to possess anticonvulsant activity in various models of seizures, acting as α-amino-3-hydroxy-5-methyl-isoxazole-4-propionate (AMPA) receptor antagonist.     

Assessment of mite fauna in different coffee cropping systems in Brazil

Agro-ecological diversification may increase natural biodiversity and decrease environmental impacts caused by the intensification of management practices, especially with respect to pest control. This study aimed to evaluate mite populations from surveys in commercial coffee (Coffea arabica) orchards managed in different ways. Four different cropping systems were compared: a conventional system (CS), non-pesticide system (NPS), organic system (OS) and organic agroforestry system (OAS). Mite samples were taken from 24 coffee plantations (n?=?6 for each management strategy). Six leaves per plant were collected from five sampling sites totalling 30 leaves from each plantation. Mites were removed from individual leaves, counted and identified to family level. Amongst the predatory mites, two families were detected; the Phytoseiidae was the most abundant family while the Stigmaeidae, generalist predatory mites, were only found in two management systems (NPS and AOS). Of the two families of phytophagous mites, the family Tenuipalpidae was the most abundant, but rarely found in AOS. The other phytophagous family, Tetranychidae, was less abundant in coffee crops than Tenuipalpidae, but the most abundant phytophagous family in CS. Understanding the relationship between mite populations and management practices can aid in choice of spraying strategies for different coffee management systems.     

Impact of naturalistic lighting on hospitalized stroke patients in a rehabilitation unit: Design and measurement

Introduction and rationale: Stroke is a major cause of acquired cerebral disability among adults, frequently accompanied by depression, anxiety, cognitive impairment, disrupted sleep and fatigue. New ways of intervention to prevent these complications are therefore needed. The major circadian regulator, the suprachiasmatic nucleus, is mainly controlled by natural daylight, and the blue spectrum is considered the most powerful. During stroke rehabilitation, patients typically are mostly indoors and therefore not exposed to the natural daytime variation in light intensity. Furthermore, several rehabilitation hospitals may be exposed to powerful light in the blue spectrum, but at a time that is adversely related to their endogenous circadian phase, for example in the late evening instead of the daytime. Hypothesis: Naturalistic light that mimics the natural daytime spectrum variation will have a positive impact on the health of poststroke patients admitted to rehabilitation. We test specifically for improved sleep and less fatigue (questionnaires, polysomnography, Actiwatch), improved well-being (questionnaires), lessen anxiety and depression (questionnaires), improved cognition (tests), stabilizing of the autonomous nervous system (ECG/HR, blood pressure, temperature) and stabilizing of the diurnal biochemistry (blood markers). Study design: The study is a prospective parallel longitudinal randomized controlled study (quasi randomization). Stroke patients in need of rehabilitation will be included at the acute stroke unit and randomized to either the intervention unit (naturalistic lighting) or the control unit (CU) (standard lighting). The naturalistic light is installed in the entire IU (Cromaviso, Denmark). Conclusion: This study aims to elucidate the influence of naturalistic light on patients during long-term hospitalization in a real hospital setting. The hypotheses are based on preclinical research, as studies using naturalistic light have never been performed before. Investigating the effects of naturalistic light in a clinical setting is therefore much needed.     

Interactions Between the Circadian Clock and Heme Oxygenase in the Retina of <Emphasis Type="Italic">Drosophila melanogaster</Emphasis>

The Drosophila retina has an autonomous peripheral circadian clock in which the expression of the gene encoding heme oxygenase (HO) is under circadian control with the ho mRNA peaking at the beginning of the day and in the middle of the night. The function of HO in the retina is unknown, but we observed that it regulates the circadian clock and protects photoreceptors against DNA damage. The decline in HO level increases and decreases the expression of the canonical clock genes period (per) and Clock (Clk), respectively. The opposite result was observed after increasing HO expression. Among three products of HO activity—carbon monoxide (CO), ferrous ions, and biliverdin—the latter has no effect on per and Clk expressions, but CO exerts the same effect as the increase of ho expression. This suggests that HO action on the clock is mediated by CO, which may affect Clk expression during the day and the level of per expression. While ho expression is not stimulated by nitric oxide (NO), NO has the same effect on the clock as HO, increasing Clk expression and decreasing the expression of per.