scholarly journals Bees may drive the reproduction of four sympatric cacti in a vanishing coastal mediterranean-type ecosystem

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7865
Author(s):  
Pablo C. Guerrero ◽  
Claudia A. Antinao ◽  
Beatriz Vergara-Meriño ◽  
Cristian A. Villagra ◽  
Gastón O. Carvallo
Keyword(s):  
Interannual Variation ◽  
Mating Systems ◽  
Pollen Limitation ◽  
Statistical Significance ◽  
Sympatric Species ◽  
Reproductive Assurance ◽  
Hand Pollination ◽  
Mediterranean Type Ecosystem ◽  
Pollinator Assemblage ◽  
And Control

Background Sympatric congeneric plants might share pollinators, or each species might avoid competition by evolving specialized traits that generate partitions in pollinator assemblages. In both cases, pollen limitation (a decrease in the quality and quantity of compatible reproductive pollen) can occur, driving the plant mating system to autogamy as a mechanism of reproductive assurance. We assessed the relationships between pollinator assemblages and mating systems in a group of sympatric congeneric plants. We attempted to answer the following questions: (i) How similar are pollinator assemblages among sympatric cactus species? (ii) Which mating systems do sympatric cactus species use? Methods We studied sympatric Eriosyce taxa that inhabit a threatened coastal strip in a mediterranean-type ecosystem in central Chile. We performed field observations on four taxa and characterized pollinators during the years 2016 and 2017. We estimated differences in the pollinator assemblages using the Bray–Curtis index. To elucidate the mating systems, we conducted hand-pollination experiments using three treatments: manual cross-pollination, automatic self-pollination, and control (unmanipulated individuals). We tested differences in seed production for statistical significance using Kruskal–Wallis analysis. Results Eriosyce subgibbosa showed a distinctive pollinator assemblage among the sympatric species that we studied (similarity ranged from 0% to 8%); it was visited by small bees and was the only species that was visited by the giant hummingbird Patagona gigas. Pollinator assemblages were similar between E. chilensis (year 2016 = 4 species; 2017 = 8) and E. chilensis var. albidiflora (2016 = 7; 2017 = 4); however, those of E. curvispina var. mutabilis (2016 = 7; 2017 = 6) were less similar to those of the aforementioned species. E. curvispina var. mutabilis showed the highest interannual variation in its pollinator assemblage (18% similarity). Reproduction in E. subgibbosa largely depends on pollinators, although it showed some degree of autogamy. Autonomous pollination was unfeasible in E. chilensis, which depended on flower visitors for its reproductive success. Both E. chilensis var. albidiflora and E. curvispina var. mutabilis showed some degree of autogamy. Discussion We observed differences in pollinator assemblages between E. subgibbosa and the remaining Eriosyce taxa, which depend on hymenopterans for pollen transfer. Pollinator assemblages showed considerable interannual variation, especially those of E. subgibbosa (ornithophilous syndrome) and E. curvispina var. mutabilis (melitophilous syndrome). Autogamous reproduction in these taxa may act as a reproductive assurance mechanism when pollinator availability is unpredictable. Our study contributes to improving our understanding of the reproductive systems of ecological interactions between threatened species in a Chilean mediterranean-type ecosystem.

scholarly journals Pollination of two species of Vellozia (Velloziaceae) from high-altitude quartzitic grasslands, Brazil

2007 ◽  
Vol 21 (2) ◽  
pp. 325-333 ◽  
Author(s):  
Claudia Maria Jacobi ◽  
Mário César Laboissiérè del Sarto
Keyword(s):  
High Altitude ◽  
Pollen Limitation ◽  
Cross Pollination ◽  
Se Brazil ◽  
Self Compatibility ◽  
Leaf Cutting ◽  
Pollen Theft ◽  
Floral Displays ◽  
Facultative Xenogamy ◽  
And Control

The pollinators and breeding system of two species of Vellozia (Velloziaceae) from high-altitude quartzitic grasslands in SE Brazil were studied. Vellozia leptopetala is shrubby and grows solely on rocky outcrops, V. epidendroides is herbaceous and grows on stony soils. Both bear solitary, hermaphrodite flowers, and have massive, short-lasting annual blooms. We evaluated the level of self-compatibility and need for pollinators of 50 plants of each species and 20-60 flowers per treatment: hand self- and cross-pollination, spontaneous pollination, agamospermy and control. The behavior of floral visitors on flowers and within plants was recorded. Both species are mostly self-incompatible, but produce a small number of seeds by self-fertilization. The pollen-ovule ratio suggests facultative xenogamy. They were visited primarily by bees, of which the most important pollinators were two leaf-cutting bees (Megachile spp.). Vellozia leptopetala was also pollinated by a territorial hummingbird. Low natural seed production compared to cross-pollination seed numbers suggests that pollen limitation is the main cause of low seed set. This was attributed to the combined effect of five mechanisms: selfing prior to anthesis, enhanced geitonogamy as a result of large floral displays, low number of visits per flower for the same reason, pollen theft by many insect species, and, in V. leptopetala, delivery of mixed pollen loads on the stigma as a consequence of hummingbird promiscuity.

scholarly journals Effects of two different deep digital flexor tenotomy techniques on distal articular angles of equine cadaver forelimbs

2012 ◽  
Vol 42 (11) ◽  
pp. 2005-2010
Author(s):  
Antonio Cezar de Oliveira Dearo ◽  
Vitor Bruno Bianconi Rosa ◽  
Peter Reichmann ◽  
Milton Luis Ribeiro de Oliveira
Keyword(s):  
Quantitative Data ◽  
Statistical Significance ◽  
Surgical Approaches ◽  
Control Groups ◽  
Before And After ◽  
Distal Interphalangeal ◽  
The Difference ◽  
And Control ◽  
Flexor Tenotomy

Deep digital flexor (DDF) tenotomy is a technique employed for years to treat selected disorders of the musculoskeletal system in horses. Although two different surgical approaches (i.e. mid-metacarpal and pastern) have been described for performing the procedure, in vitro quantitative data regarding the modifications induced by either technique on the distal articular angles is lacking. Therefore, the purpose of the study reported here was to investigate the viability of a proposed biomechanical system of induced-traction used to compare the two DDF tenotomy techniques by measuring the distal articular angles of equine cadaver forelimbs. Ten pairs of forelimbs were collected and mounted to a biomechanical system developed to apply traction at the toe level. Dorsal articular angles of the metacarpophalangeal (MP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints were determined by geometric lines on radiographs taken before and after performing each technique. Comparisons between each tenotomy group and its own control, for each joint, and between the two tenotomy groups using as variable the difference between the tenotomy and control groups were tested. Despite the lack of statistical significance, the DDF tenotomy technique at the pastern level produced extension, to a lesser and greater extent, of the PIP and DIP joints, respectively when compared to the mid-metacarpal level. No remarkable differences could be observed for the MP joint. The developed traction-induced biomechanical construct seemed to be effective in producing valuable quantitative estimations of the distal articular angles of equine cadaver forelimbs subjected to different DDF tenotomy techniques.

scholarly journals Discharge Properties of MST Neurons That Project to the Frontal Pursuit Area in Macaque Monkeys

2005 ◽  
Vol 94 (2) ◽  
pp. 1084-1090 ◽  
Author(s):  
Anne K. Churchland ◽  
Stephen G. Lisberger
Keyword(s):  
Optic Flow ◽  
Action Potentials ◽  
Rhesus Monkeys ◽  
Statistical Significance ◽  
Image Motion ◽  
Antidromic Activation ◽  
Medial Superior Temporal ◽  
Mst Neurons ◽  
Direction Tuning ◽  
And Control

We have used antidromic activation to determine the functional discharge properties of neurons that project to the frontal pursuit area (FPA) from the medial-superior temporal visual area (MST). In awake rhesus monkeys, MST neurons were considered to be activated antidromically if they emitted action potentials at fixed, short latencies after stimulation in the FPA and if the activation passed the collision test. Antidromically activated neurons ( n = 37) and a sample of the overall population of MST neurons ( n = 110) then were studied during pursuit eye movements across a dark background and during laminar motion of a large random-dot texture and optic flow expansion and contraction during fixation. Antidromically activated neurons showed direction tuning during pursuit (25/37), during laminar image motion (21/37), or both (16/37). Of 27 neurons tested with optic flow stimuli, 14 showed tuning for optic flow expansion ( n = 10) or contraction ( n = 4). There were no statistically significant differences in the response properties of the antidromically activated and control samples. Preferred directions for pursuit and laminar image motion did not show any statistically significant biases, and the preferred directions for eye versus image motion in each sample tended to be equally divided between aligned and opposed. There were small differences between the control and antidromically activated populations in preferred speeds for laminar motion and optic flow; these might have reached statistical significance with larger samples of antidromically activated neurons. We conclude that the population of MST neurons projecting to the FPA is highly diverse and quite similar to the general population of neurons in MST.

scholarly journals THE IMPORTANCE OF EDUCATION TO REDUCE SELF-DESTRUCTIVE NAIL HABITS

2021 ◽  
Vol 4 ◽  
pp. 491-499
Author(s):  
Ilze Upeniece ◽  
Monta Beltiņa
Keyword(s):  
Clinical Practice ◽  
General Education ◽  
Statistical Significance ◽  
Target Population ◽  
Control Group ◽  
Age Related ◽  
Nail Changes ◽  
Group 2 ◽  
And Control ◽  
Traumatic Damage

Onychophagia and onychotillomania are rarely seen in clinical practice and are considered undervalued. The study aims were to determine the prevalence of onychophagia and onychotillomania habit in the patient group with hand nail damage and control group, to determine which would be the target population to educate. Patients were interviewed about self-destructive habits. Excel and SPSS were used for data analysis. In the nail damage group, 28.6% of the respondents showed self-destructive habits and past habits – 31.4%. In the control group, the result was 22.9% and 31.4%. For 74.3% of patients the cause of nail damage was skin disease (including 61.54% of respondents with nail damage who have psoriasis), for 5.7% it was age-related nail changes, for 20% traumatic damage and for 57.14% of them it was a result of self-destructive habit. In the nail damage group both – present and past self-destructive habits are higher than in the control group, but it has no statistical significance (p=0.785). 1)The prevalence of onychophagia and onychotillomania does not differ between patients and control group. 2)General education of the population is necessary to actualize this problem, which can worsen nail changes.

scholarly journals Impact of ascorbic acid in reducing the incidence of vancomycin associated nephrotoxicity in critically ill patients: A preliminary randomized controlled trial

F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 929
Author(s):  
Nouran Hesham El-Sherazy ◽  
Naglaa Samir Bazan ◽  
Sara Mahmoud Shaheen ◽  
Nagwa A. Sabri
Keyword(s):  
Ascorbic Acid ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Statistical Significance ◽  
Intervention Group ◽  
Secondary Outcome ◽  
Control Group ◽  
Control Groups ◽  
The Absolute ◽  
And Control

Background Antioxidants show nephroprotective effect against vancomycin associated nephrotoxicity (VAN) in animals. This study aimed to assess the ascorbic acid nephro-protective role against VAN clinically. Methods Forty-one critically ill patients were randomly assigned to one of two groups: intervention group (vancomycin IV plus ascorbic acid, n=21) or control group (vancomycin IV only, n=20). Primary outcomes were the incidence of VAN and the absolute change in creatinine parameters, while mortality rate was the secondary outcome. Nephrotoxicity was defined as an increase in serum creatinine (S.cr) by at least 0.5 mg/dL or 50% of baseline for at least two successive measurements. This study is registered at Clinicaltrials.gov (NCT03921099), April 2019. Results Mean absolute S.cr increase was significant when compared between both groups, P-value = 0.036, where S.cr increased by 0.05(0.12) and 0.34(0.55) mg/dL in the intervention and control groups, respectively. Mean absolute Cr.cl decline was significant when compared between both groups, P-value = 0.04, where Cr.cl was decreased by 5.9(17.8) and 22.3(30.4) ml/min in the intervention and control groups, respectively. Incidence of VAN was 1/21(4.7%) versus 5/20(25%) in the intervention and control groups, respectively (RR: 0.19; CI: 0.024–1.49; P-value = 0.093). Mortality was higher in the control group; however, it was not statistically significant, P-value = 0.141. Conclusion Co-administration of ascorbic acid with vancomycin preserved renal function and reduced the absolute risk of VAN by 20.3%, however, the reduction in VAN incidence didn’t reach statistical significance level. Further large multicenter prospective trials are recommended.

scholarly journals The Impact of Divergent and Convergent Tasks on Iraqi EFL Students Reading Comprehension Success

2021 ◽  
Vol 1 (1) ◽  
pp. 35-39
Author(s):  
Sabeeha Hamza Dehham ◽  
Nadia Majeed Hussein
Keyword(s):  
Reading Skills ◽  
Experimental Approach ◽  
Statistical Significance ◽  
Control Group ◽  
Efl Students ◽  
Preparatory Stage ◽  
The Mean ◽  
And Control ◽  
The Impact ◽  
Experimental Group

This research attempted to explore the effects of divergent and convergent tasks on the successful reading of EFL students at the preparatory stage. To verify the analysis, the null hypothesis was established that states "There are no differences of statistical significance at the level of (0,05) among the mean of scores of the experimental group who study according to divergent and convergent task technique and the mean of the scores of the control group who study according to the regular method".  The experimental approach is used by designing two equivalent experimental groups of 32 students studying the technique proposed, and an 8-week (2019-2020) control group of 32 students, three classes each week using the Google Classroom Platform and Telegram. The present study utilized the platform Google Classroom (GC) and Telegram as an educational platform to assist students during their course learning process. The writing skills test was administered after checking with the experts. The results show that there are statistical differences at level (0,05) between the average of the experimental and control groups' reading skills and those of the experimental group. This difference is because the experimental group uses divergent and convergent tasks.

scholarly journals Oxidative Stress in BPH

2009 ◽  
Vol 48 (173) ◽  
Author(s):  
Murat Savas ◽  
A Verit ◽  
H Ciftci ◽  
E Ciftci ◽  
E Aktan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Statistical Significance ◽  
Previous Treatment ◽  
Oxidative Status ◽  
Prostatic Hyperplasia ◽  
Newly Diagnosed ◽  
Antioxidative Status ◽  
Total Antioxidant ◽  
And Control ◽  
The Relationship

INTRODUCTION:In the present study, we investigated the relationship between potency of oxidative stress and BPH and this may assist to contribute to the realistic explanation of the ethiopathogenesis of BPH.METHODS:Seventy four newly diagnosed men with BPH (mean age: 54+/-11.2), who had not undergone any previous treatment for BPH, and 62 healthy volunteers (mean age: 55+/-14) were enrolled in the present study. To determine the antioxidative status of plasma, total antioxidant capacity (TAC) was calculated, and to determine the oxidative status of plasma (TOS) total peroxide levels were measured. The ratio of TAC to total peroxide was accepted as an indicator of oxidative stress (OSI). Data are presented as mean SD +/- unless specified. Student t-test and correlation analyses were used to evaluate the statistical significance differences in the median values recorded for all parameters between BPH and control group.RESULTS:Plasma TAC TOS were found in patients and controls (1.70 +/- 0.32, 1.68 +/- 0.19 micromol Trolox Equiv./L), (12.48 +/- 1.98, 12.40 +/- 1.14 micromol / L) respectively. OSI was calculated as 7.57 +/- 1.91, 7.48 +/- 1.33, respectively. Plasma TAC, TOS and OSI levels were not found to be significantly difference between patients and control subjects (p>0.05, p>0.05, p>0.05).CONCLUSIONS:The present study has shown that there were not relationship between potency of oxidative stress and BPH. Further well designed studies should be planned to find out whether the oxidative stress-related parameters play role in BPH as an interesting pathology in regard of the etiopathogenesis.Keywords: benign prostatic hyperplasia, oxidative stress, prostate

Predator Effects on Plant-Pollinator Interactions, Plant Reproduction, Mating Systems, and Evolution

2020 ◽  
Vol 51 (1) ◽  
pp. 319-340
Author(s):  
Amanda D. Benoit ◽  
Susan Kalisz
Keyword(s):  
Mating Systems ◽  
Seed Set ◽  
Pollen Limitation ◽  
Plant Traits ◽  
Plant Reproduction ◽  
Trophic Levels ◽  
Interaction Networks ◽  
Pollinator Abundance ◽  
Plant Pollinator ◽  
Predator Effects

Plants are the foundation of the food web and therefore interact directly and indirectly with myriad organisms at higher trophic levels. They directly provide nourishment to mutualistic and antagonistic primary consumers (e.g., pollinators and herbivores), which in turn are consumed by predators. These interactions produce cascading indirect effects on plants (either trait-mediated or density-mediated). We review how predators affect plant-pollinator interactions and thus how predators indirectly affect plant reproduction, fitness, mating systems, and trait evolution. Predators can influence pollinator abundance and foraging behavior. In many cases, predators cause pollinators to visit plants less frequently and for shorter durations. This decline in visitation can lead to pollen limitation and decreased seed set. However, alternative outcomes can result due to differences in predator, pollinator, and plant functional traits as well as due to altered interaction networks with plant enemies. Furthermore, predators may indirectly affect the evolution of plant traits and mating systems.

scholarly journals Detection of internal N7-methylguanosine (m7G) RNA modifications by mutational profiling sequencing

2019 ◽  
Vol 47 (20) ◽  
pp. e126-e126 ◽  
Author(s):  
Christel Enroth ◽  
Line Dahl Poulsen ◽  
Søren Iversen ◽  
Finn Kirpekar ◽  
Anders Albrechtsen ◽  
...  
Keyword(s):  
Statistical Significance ◽  
Yeast Cells ◽  
Alignment Error ◽  
Rna Modifications ◽  
Abasic Sites ◽  
Mutational Profiling ◽  
Domains Of Life ◽  
High Throughput Detection ◽  
Nucleotide Resolution ◽  
And Control

Abstract Methylation of guanosine on position N7 (m7G) on internal RNA positions has been found in all domains of life and have been implicated in human disease. Here, we present m7G Mutational Profiling sequencing (m7G-MaP-seq), which allows high throughput detection of m7G modifications at nucleotide resolution. In our method, m7G modified positions are converted to abasic sites by reduction with sodium borohydride, directly recorded as cDNA mutations through reverse transcription and sequenced. We detect positions with increased mutation rates in the reduced and control samples taking the possibility of sequencing/alignment error into account and use replicates to calculate statistical significance based on log likelihood ratio tests. We show that m7G-MaP-seq efficiently detects known m7G modifications in rRNA with mutational rates up to 25% and we map a previously uncharacterised evolutionarily conserved rRNA modification at position 1581 in Arabidopsis thaliana SSU rRNA. Furthermore, we identify m7G modifications in budding yeast, human and arabidopsis tRNAs and demonstrate that m7G modification occurs before tRNA splicing. We do not find any evidence for internal m7G modifications being present in other small RNA, such as miRNA, snoRNA and sRNA, including human Let-7e. Likewise, high sequencing depth m7G-MaP-seq analysis of mRNA from E. coli or yeast cells did not identify any internal m7G modifications.

Sign in / Sign up

Export Citation Format

Share Document