356 research outputs found
Regeneration Response to Salvage Logging Following Tornado Disturbance
In an era of increasing natural disturbances, successful tree regeneration has grown more difficult to achieve. Salvage logging, a common management response to disturbance, may further impede regeneration success, although published literature currently remains inconclusive. In 2013, a rare tornado in northcentral Maine, USA, and subsequent salvage operation created three clear âtreatmentsâ for evaluation of post-disturbance regeneration: blowdown, blowdown followed by salvage logging and an undisturbed control. In the summers of 2022 and 2023, (nine and ten) years post-tornado, we revisited this site to examine regeneration outcomes.
During the summer of 2022, we evaluated stand structure and regeneration success of the sapling layer. Our objectives focused on understanding (1) how salvage logging alters regeneration abundance and species composition of woody species and (2) whether the greater abundance of coarse woody material (CWM) remaining in the blowdown restricts moose browse through a natural âexclosure effectâ. We inventoried tree regeneration within these treatments to evaluate differences in sapling abundance, species composition, size structure, and browsing intensity. In addition, we inventoried CWM, including the height above forest floor. Results revealed significant differences in sapling composition and browsing intensity among treatments with the salvage treatment containing the highest proportion of browsed saplings. Binomial generalized linear models revealed that browsing probability was a function of mean CWM height and an interaction between sapling density and proportion of sapling hardwoods. Thus, browsing damage was less likely in plots with greater CWM heights and more likely in plots with greater sapling density and more hardwood saplings.
During the summer of 2023, we revisited these stands to understand treatment effects on understory plant communities and microclimates. Our objectives explore (1) understory community differences among undisturbed, blowdown and salvage conditions, (2) relationships between conifer sapling abundance and early successional, recalcitrant species, and (3) relationships between microclimate factors and understory communities. We inventoried understory vegetation, took hemispherical photographs to characterize canopy openness and installed sensors to track temperature and soil moisture throughout the growing season. Results indicate distinct understory community differences among each of the treatments, with the salvage treatment supporting a higher richness and abundance of early successional, shade intolerant taxa, while the blowdown and control treatments were characterized by later successional, shade tolerant taxa. Abundance of conifer regeneration was notably lower in plots with high abundance of Rubus idaeus or Pteridium aquilinum. Ordination results suggest that canopy openness and surface temperature fluctuations were the primary factors associated with these compositional differences.
This study furthers our understanding of ecosystem recovery following the successive disturbances of blowdown and salvage logging. Results suggest that salvage logging created important differences in CWM abundance and height distribution, when compared to un-salvaged areas, and that these differences in turn altered sapling size structure and browsing intensity. Further, distinct differences in species ordination and microclimate results suggest salvage logging may create conditions more favorable to shade-intolerant, recalcitrant understory vegetation. Together, these findings highlight the potential long-term effects of successive disturbances and provide forest managers insight on possible post-disturbance conditions
âI was worried if I donât have a broken leg they might not take it seriouslyâ: Experiences of men accessing ambulance services for mental health and/or alcohol and other drug problems
Abstract Background A large proportion of ambulance callouts are for men with mental health and/or alcohol and other drug (AOD) problems, but little is known about their experiences of care. This study aimed to describe men's experiences of ambulance care for mental health and/or AOD problems, and factors that influence their care. Methods Interviews were undertaken with 30 men who used an ambulance service for mental health and/or AOD problems in Australia. Interviews were analysed using the Framework approach to thematic analysis. Results Three interconnected themes were abstracted from the data: (a) professionalism and compassion, (b) communication and (c) handover to emergency department staff. Positive experiences often involved paramedics communicating effectively and conveying compassion throughout the episode of care. Conversely, negative experiences often involved a perceived lack of professionalism, and poor communication, especially at handover to emergency department staff. Conclusion Increased training and organizational measures may be needed to enhance paramedics' communication when providing care to men with mental health and/or AOD problems
Eurasian and African mitochondrial DNA influences in the Saudi Arabian population
BACKGROUND: Genetic studies of the Arabian Peninsula are scarce even though the region was the center of ancient trade routes and empires and may have been the southern corridor for the earliest human migration from Africa to Asia. A total of 120 mtDNA Saudi Arab lineages were analyzed for HVSI/II sequences and for haplogroup confirmatory coding diagnostic positions. A phylogeny of the most abundant haplogroup (preHV)1 (R0a) was constructed based on 13 whole mtDNA genomes. RESULTS: The Saudi Arabian group showed greatest similarity to other Arabian Peninsula populations (Bedouin from the Negev desert and Yemeni) and to Levantine populations. Nearly all the main western Asia haplogroups were detected in the Saudi sample, including the rare U9 clade. Saudi Arabs had only a minority sub-Saharan Africa component (7%), similar to the specific North-African contribution (5%). In addition, a small Indian influence (3%) was also detected. CONCLUSION: The majority of the Saudi-Arab mitochondrial DNA lineages (85%) have a western Asia provenance. Although the still large confidence intervals, the coalescence and phylogeography of (preHV)1 haplogroup (accounting for 18 % of Saudi Arabian lineages) matches a Neolithic expansion in Saudi Arabia
Unaltered myocilin expression in the blood of primary open angle glaucoma patients
PURPOSE: To investigate the expression of the myocilin gene (MYOC) in the blood of primary open angle glaucoma (POAG) patients to determine if altered systemic expression is playing a role.
METHODS: Patients (n=47) were eligible for inclusion if they met standard clinical criteria for POAG. Control subjects (n=27) were recruited who were free from glaucoma by examination. RNA was extracted from leukocytes of patients and controls and converted to cDNA by reverse transcriptase enzyme, and quantitative PCR was used to assess expression levels of MYOC and the house keeping gene ÎČ-globulin (HBB). The ratio of MYOC expression to HBB expression for POAG patients was compared to that of controls and to clinical characteristics of POAG patients.
RESULTS: Mean gene expression values were statistically similar in POAG patients and controls for both MYOC (pâ€0.55) and HBB (pâ€0.48). MYOC/HBB ratios were also statistically indistinguishable between POAG patients and controls (pâ€0.90). MYOC/HBB ratios were not significantly associated with age, sex, or ethnicity of patients within the POAG group. Similarly, MYOC/HBB ratios were not significantly associated with clinical parameters related to POAG severity, including maximum intraocular pressure, vertical cup-to-disk ratio, static perimetry mean deviation, or static perimetry pattern standard deviation.
CONCLUSIONS: MYOC expression is not altered in the blood of POAG patients, unlike MYOC expression in trabecular meshwork (TM) cultures. These results suggests that MYOC expression is not altered systemically but rather that MYOC expression may contribute to POAG pathogenesis in specific tissues such as TM
Absence of altered expression of optineurin in primary open angle glaucoma patients
PURPOSE: To investigate the expression level of the optineurin gene (OPTN) in the blood of primary open angle glaucoma (POAG) patients to determine if altered expression is playing a role in primary open angle glaucoma systemically.
METHODS: Patients (n=47) were eligible for inclusion if they met standard clinical criteria for POAG, including age greater than 40 years, intraocular pressure â„21 mmHg in at least one eye before treatment, normal-appearing anterior chamber angles bilaterally on gonioscopy, and optic nerve injury characteristic of POAG. Control subjects (n=27) were recruited who were free from glaucoma by examination. DNA from patient was sequenced to look for possible mutations in the coding region of OPTN or its promoter. RNA was extracted from leukocytes of patients and controls and converted to cDNA by reverse transcriptase enzyme, and quantitative PCR was used to assess expression levels of OPTN and the ÎČ-globulin gene. The ratio of OPTN expression to ÎČ-globulin gene expression for POAG patients was compared to that of controls and to clinical characteristics of POAG patients.
RESULTS: No mutation(s) were detected in any of the patients after sequencing the full OPTN gene and its promoter region. Mean OPTN (pâ€0.35), and ÎČ-globulin (pâ€0.48) gene expression values were statistically similar in POAG patients and controls. OPTN/ÎČ-globulin (pâ€0.83) ratios were also indistinguishable between POAG patients and controls. OPTN/ÎČ-globulin ratios were not significantly associated with age, sex, or ethnicity of patients within the POAG group. Similarly, OPTN/ÎČ-globulin ratios were not significantly affected by ethnicity or clinical parameters related to POAG severity including maximum intraocular pressure, vertical cup-to-disk ratio, static perimetry mean deviation, or static perimetry pattern standard deviation.
CONCLUSIONS: OPTN expression is not altered in the blood of POAG patients, suggesting that OPTN expression is not changed systemically and implying that other mechanisms are involved in POAG pathogenesis
High-resolution analysis of DNA copy number alterations in patients with primary open-angle glaucoma
PURPOSE: To determine whether patients with isolated primary open-angle glaucoma (POAG) have evidence of chromosomal copy number alterations.
METHODS: Twenty-seven Caucasian and African-American POAG patients and 12 ethnically matched controls were carefully screened for possible glaucoma and tested for chromosomal copy number alterations using high resolution array comparative genomic hybridization.
RESULTS: No POAG patient had evidence of chromosomal copy number alterations when compared to normal ethnically matched controls. Additionally, there was no evidence of somatic mosaicism in any tested POAG patient.
CONCLUSIONS: Chromosomal deletions and/or duplications were not detected in POAG patients as compared to controls. Other chromosomal imbalances such as translocations, inversions, and some ploidies cannot be detected by current array comparative genomic hybridization technology, and other nuclear genetic, mitochondrial abnormalities, or epigenetic factors cannot be excluded as a possible contributing factor to POAG pathogenesis
A de novo marker chromosome derived from 9p in a patient with 9p partial duplication syndrome and autism features: genotype-phenotype correlation
<p>Abstract</p> <p>Background</p> <p>Previous studies focusing on candidate genes and chromosomal regions identified several copy number variations (CNVs) associated with increased risk of autism or autism spectrum disorders (ASD).</p> <p>Case Presentation</p> <p>We describe a 17-year-old girl with autism, severe mental retardation, epilepsy, and partial 9p duplication syndrome features in whom GTG-banded chromosome analysis revealed a female karyotype with a marker chromosome in 69% of analyzed metaphases. Array CGH analysis showed that the marker chromosome originated from 9p24.3 to 9p13.1 with a gain of 38.9 Mb. This mosaic 9p duplication was detected only in the proband and not in the parents, her four unaffected siblings, or 258 ethnic controls. Apart from the marker chromosome, no other copy number variations (CNVs) were detected in the patient or her family. Detailed analysis of the duplicated region revealed: i) an area extending from 9p22.3 to 9p22.2 that was previously identified as a critical region for the 9p duplication syndrome; ii) a region extending from 9p22.1 to 9p13.1 that was previously reported to be duplicated in a normal individual; and iii) a potential ASD locus extending from 9p24.3 to 9p23. The ASD candidate locus contained 34 genes that may contribute to the autistic features in this patient.</p> <p>Conclusion</p> <p>We identified a potential ASD locus (9p24.3 to 9p23) that may encompass gene(s) contributing to autism or ASD.</p
Down-regulation of OPA1 in patients with primary open angle glaucoma
PURPOSE: Heterozygous optic atrophy type1 (OPA1) mutations are responsible for dominant optic atrophy, and the down regulation of OPA1 expression in patients with Leber hereditary optic neuropathy may imply that Opa1 protein levels in mitochondria play a role in other spontaneous optic neuropathies as well. Mitochondrial and metabolic abnormalities may put the optic nerve at risk in primary open angle glaucoma (POAG), and this preliminary study was designed to investigate whether altered OPA1 expression might be present in the progressive optic neuropathy of POAG.
METHODS: Patients were eligible for inclusion if they met standard clinical criteria for POAG, including age greater than 40 years, intraocular pressure â„ 21 mmHg in at least one eye before treatment, normal-appearing anterior chamber angles bilaterally on gonioscopy, and optic nerve injury characteristic of POAG. RNA was extracted from leukocytes and converted to cDNA by reverse transcriptase enzyme, and real time PCR was used to assess expression levels of OPA1 and the ÎČ-globulin (HBB) housekeeping gene. The ratio of OPA1 expression to HBB expression (OPA1/HBB) for POAG patients was compared to that of controls and to clinical characteristics of POAG patients.
RESULTS: Forty-three POAG patients and 27 controls were completely phenotyped with a full ophthalmologic examination and static perimetry. Mean age (POAG 67.9 years; controls 61.8 years) and sex (POAG 26 males/17 females; controls 11/16) were similar for the two groups. Mean OPA1/HBB of POAG patients (1.16, SD 0.26) was 18% lower than controls (1.41, SD 0.50), and this difference was statistically significant (pâ€0.021). OPA1 expression differed between the groups (pâ€0.037), but HBB expression did not differ (pâ€0.24). OPA1/HBB was not correlated with any clinical feature of POAG patients.
CONCLUSIONS: Transcriptional analysis of peripheral blood leucocytes is a limited model system for studying the consequences of mitochondrial abnormalities in the optic nerve. Nevertheless, OPA1 is known to affect mitochondrial stability and has now been implicated in several spontaneous optic neuropathies. Decreased OPA1 expression in POAG patients is another indication that mitochondrial function, and possibly mitochondrially-induced apoptosis, may play a role in the development of POAG
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