Effect of mastication and other mechanical treatments on fuel structure in chaparral

2015 ◽  
Vol 24 (7) ◽  
pp. 949 ◽  
Author(s):  
Teresa J. Brennan ◽  
Jon E. Keeley

Mechanical fuel treatments are a common pre-fire strategy for reducing wildfire hazard that alters fuel structure by converting live canopy fuels to a compacted layer of dead surface fuels. Current knowledge concerning their effectiveness, however, comes primarily from forest-dominated ecosystems. Our objectives were to quantify and compare changes in shrub-dominated chaparral following crushing, mastication, re-mastication and mastication-plus-burning treatments, and to assess treatment longevity. Results from analysis of variance (ANOVA) identified significant differences in all fuel components by treatment type, vegetation type and time since treatment. Live woody fuel components of height, cover and mass were positively correlated with time since treatment, whereas downed woody fuel components were negatively correlated. Herbaceous fuels, conversely, were not correlated, and exhibited a 5-fold increase in cover across treatment types in comparison to controls. Average live woody fuel recovery was 50% across all treatment and vegetation types. Differences in recovery between time-since-treatment years 1–8 ranged from 32–65% and exhibited significant positive correlations with time since treatment. These results suggest that treatment effectiveness is short term due to the rapid regrowth of shrubs in these systems and is compromised by the substantial increase in herbaceous fuels. Consequences of not having a full understanding of these treatments are serious and leave concern for their widespread use on chaparral-dominated landscapes.

Diagnostics ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 353
Author(s):  
Ha Eun Jeon ◽  
Hyun Mi Kang ◽  
Eun Ae Yang ◽  
Hye Young Han ◽  
Seung Beom Han ◽  
...  

The aim of the present study is to re-evaluate the clinical application of two-times serologic immunoglobulin M (IgM) tests using microparticle agglutination assay (MAA), an enzyme-linked immunosorbent assay (ELISA), and polymerase chain reaction (PCR) assay in diagnosing Mycoplasma pneumoniae (MP) infection. A retrospective analysis of 62 children with MP pneumonia during a recent epidemic (2019–2020) was conducted. The MAA and ELISA immunoglobulin M (IgM) and IgG measurements were conducted twice at admission and around discharge, and MP PCR once at presentation. Diagnostic rates in each test were calculated at presentation and at discharge. The seroconverters were 39% (24/62) of patients tested by MAA and 29% (18/62) by ELISA. At presentation, the diagnostic positive rates of MAA, ELISA, and PCR tests were 61%, 71%, and 52%, respectively. After the second examination, the rates were 100% in both serologic tests. There were positive correlations between the titers of MAA and the IgM values of ELISA. The single serologic IgM or PCR tests had limitations to select patients infected with MP in the early stage. The short-term, paired IgM serologic tests during hospitalization can reduce patient-selection bias in MP infection studies.


2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Hao Zhang ◽  
Jian Sun ◽  
Junnan Xiong

Evapotranspiration (ET) is a key factor to further our understanding of climate change processes, especially on the Tibetan Plateau, which is sensitive to global change. Herein, the spatial patterns of ET are examined, and the effects of environmental factors on ET at different scales are explored from the years 2000 to 2012. The results indicated that a steady trend in ET was detected over the past decade. Meanwhile, the spatial distribution shows an increase of ET from the northwest to the southeast, and the rate of change in ET is lower in the middle part of the Tibetan Plateau. Besides, the positive effect of radiation on ET existed mainly in the southwest. Based on the environment gradient transects, the ET had positive correlations with temperature (R>0.85, p<0.0001), precipitation (R > 0.89, p < 0.0001), and NDVI (R > 0.75, p < 0.0001), but a negative correlation between ET and radiation (R = 0.76, p < 0.0001) was observed. We also found that the relationships between environmental factors and ET differed in the different grassland ecosystems, which indicated that vegetation type is one factor that can affect ET. Generally, the results indicate that ET can serve as a valuable ecological indicator.


CoDAS ◽  
2014 ◽  
Vol 26 (4) ◽  
pp. 276-285
Author(s):  
Eliane Mi Chang ◽  
Clara Regina Brandão de Avila

PURPOSE: To characterize students' performance in Cycle I and II of the Elementary School (EF), in decoding, reading comprehension and underlying skills of reading, and investigate correlations between these variables, in the absence and presence of reading comprehension deficits, identified by their teachers.METHODS: 125 students from ES were grouped according to Cycle and presence or absence of reading comprehension impairments. Two Control (good readers from both Cycles) and two Research groups (poor readers from both Cycles) were established. Assessment involved: fluency and reading comprehension; oral comprehension; working and short-term phonological memory; grammar closure. It was compared (Mann-Whitney test): in intragroup study, both Control and Research groups; in intergroup study, Control and Research from different cycles, and Control I and Research II. Spearman coefficient investigated correlations.RESULTS: Analyzing reading comprehension, we observed better performance of Control Groups in all tasks in comparison to the respective Research Groups, and better performance of Control II in comparison to Control I. Research Groups had similar results in most tests. Positive correlations have been observed between most of the variables.CONCLUSION: Students without reading comprehension impairments showed better performance in reading in both Cycles. Working memory and oral comprehension did not differentiate students with and without complaints in Cycle I, differently from what was observed in Cycle II. Research II presented similar or better performance than Research I and similar or worse performance than Control I. Underlying skills showed different profiles of correlation with reading comprehension capacity, according to the group.


2011 ◽  
Vol 59 (1) ◽  
pp. 70 ◽  
Author(s):  
Sapphire J. M. McMullan-Fisher ◽  
Tom W. May ◽  
Richard M. Robinson ◽  
Tina L. Bell ◽  
Teresa Lebel ◽  
...  

Fungi are essential components of all ecosystems in roles including symbiotic partners, decomposers and nutrient cyclers and as a source of food for vertebrates and invertebrates. Fire changes the environment in which fungi live by affecting soil structure, nutrient availability, organic and inorganic substrates and other biotic components with which fungi interact, particularly mycophagous animals. We review the literature on fire and fungi in Australia, collating studies that include sites with different time since fire or different fire regimes. The studies used a variety of methods for survey and identification of fungi and focussed on different groups of fungi, with an emphasis on fruit-bodies of epigeal macrofungi and a lack of studies on microfungi in soil or plant tissues. There was a lack of replication of fire treatment effects in some studies. Nevertheless, most studies reported some consequence of fire on the fungal community. Studies on fire and fungi were concentrated in eucalypt forest in south-west and south-eastern Australia, and were lacking for ecosystems such as grasslands and tropical savannahs. The effects of fire on fungi are highly variable and depend on factors such as soil and vegetation type and variation in fire intensity and history, including the length of time between fires. There is a post-fire flush of fruit-bodies of pyrophilous macrofungi, but there are also fungi that prefer long unburnt vegetation. The few studies that tested the effect of fire regimes in relation to the intervals between burns did not yield consistent results. The functional roles of fungi in ecosystems and the interactions of fire with these functions are explained and discussed. Responses of fungi to fire are reviewed for each fungal trophic group, and also in relation to interactions between fungi and vertebrates and invertebrates. Recommendations are made to include monitoring of fungi in large-scale fire management research programs and to integrate the use of morphological and molecular methods of identification. Preliminary results suggest that fire mosaics promote heterogeneity in the fungal community. Management of substrates could assist in preserving fungal diversity in the absence of specific information on fungi.


2010 ◽  
Vol 298 (3) ◽  
pp. F502-F509 ◽  
Author(s):  
K. Mutig ◽  
T. Saritas ◽  
S. Uchida ◽  
T. Kahl ◽  
T. Borowski ◽  
...  

Vasopressin influences salt and water transport in renal epithelia. This is coordinated by the combined action of V2 receptor-mediated effects along distinct nephron segments. Modulation of NaCl reabsorption by vasopressin has been established in the loop of Henle, but its role in the distal convoluted tubule (DCT), an effective site for fine regulation of urinary electrolyte composition and the target for thiazide diuretics, is largely unknown. The Na+-Cl− cotransporter (NCC) of DCT is activated by luminal trafficking and phosphorylation at conserved NH2-terminal residues. Here, we demonstrate the effects of short-term vasopressin administration (30 min) on NCC activation in Brattleboro rats with central diabetes insipidus (DI) using the V2 receptor agonist desmopressin (dDAVP). The fraction of NCC abundance in the luminal plasma membrane was significantly increased upon dDAVP as shown by confocal microscopy, immunogold cytochemistry, and Western blot, suggesting increased apical trafficking of the transporter. Changes were paralleled by augmented phosphorylation of NCC as detected by antibodies against phospho-threonine and phospho-serine residues (2.5-fold increase at Thr53 and 1.4-fold increase at Ser71). dDAVP-induced phosphorylation of NCC, studied in tubular suspensions in the absence of systemic effects, was enhanced as well (1.7-fold increase at Ser71), which points to the direct mode of action of vasopressin in DCT. Changes were more pronounced in early (DCT1) than in late DCT as distinguished by the distribution of 11β-hydroxysteroid dehydrogenase 2 in DCT2. These results suggest that the vasopressin-V2 receptor-NCC signaling cascade is a novel effector system to adjust transepithelial NaCl reabsorption in DCT.


2020 ◽  
Author(s):  
Shoujiang You ◽  
Lixuan Wang ◽  
Huaping Du ◽  
Danni Zheng ◽  
Chongke Zhong ◽  
...  

Abstract Background The impact of elevated total homocysteine (tHcy) on functional outcomes and pneumonia after acute ischemic stroke (AIS) is still not well understood. We investigated the association between tHcy levels upon hospital admission and in-hospital short-term outcomes in AIS patients. Methods A total of 2,084 AIS patients enrolled from December 2013 to May 2014 across 22 hospitals in Suzhou city were included in the present study. We divided patients into 4 groups according to their level of admission tHcy: Q1 (<9.70 umol/L), Q2 (9.70-12.3 umol/L), Q3 (12.3-16.9 umol/L), and Q4 (≥16.9 umol/L). Logistic regression models were used to estimate the effect of tHcy on the short-term outcomes, including in-hospital pneumonia, all cause in-hospital mortality and poor outcome upon discharge (modified Rankin Scale score ≥3) in AIS patients. Results During hospitalization, 332 patients (15.9%) had pneumonia, 57 patients (2.7%) died from all causes and 784 (37.6%) patients experienced poor outcome at discharge. The risk of in-hospital pneumonia was significantly higher in patients with highest tHcy level (Q4) compared to those with lowest (Q1) (adjusted odds ratio [OR] 1.55; 95% confidence interval [CI], 1.03-2.33; P -trend =0.019). The highest tHcy level (Q4) was associated with a 3.35-fold and 1.50-fold increase in the risk of in-hospital mortality(adjusted OR 3.35; 95% CI, 1.11–10.13; P -trend =0.015) and poor outcome upon discharge(adjusted OR 1.50; 95% CI, 1.06–2.12; P -trend =0.044) in comparison to Q1 after adjustment for potential covariates including pneumonia. Subgroup analyses further confirmed a significant association between higher tHcy levels and a high risk of short-term outcomes. Conclusions Having a high admission tHcy level was independently associated with in-hospital pneumonia, all cause in-hospital mortality and poor outcome upon discharge in AIS patients. Moreover, the association between higher tHcy and poor functional outcome was not modified by pneumonia.


Blood ◽  
2012 ◽  
Vol 119 (14) ◽  
pp. 3333-3341 ◽  
Author(s):  
Catherine Léon ◽  
Katja Evert ◽  
Frank Dombrowski ◽  
Fabien Pertuy ◽  
Anita Eckly ◽  
...  

Abstract Macrothrombocytopenia in MYH9-related disease (MYH9-RD) results from defects in nonmuscular myosin-IIA function. Thrombopoietin receptor agonists (eltrombopag; romiplostim) seem to improve hemostasis, but little is known about their biologic effects in MYH9-RD. We administered romiplostim to Myh9−/− mice (100 μg/kg, every 3 days, during 1 month). MKs increased to similar numbers in Myh9−/− and wild-type (WT) mice (with an increase in immature MKs), but Myh9−/− platelet count response was much less (2.5-fold vs 8-fold increase). A strong increase in MK nuclei emboli in the lung, in WT and Myh9−/− mice, indicates increased transmigration of MKs from the BM. Prolonged (but not acute) treatment with romiplostim decreased expression of GPIb-IX-V complex and GPVI, but not of GPIIbIIIa, and bleeding time increased in WT mice. Microcirculation was not altered by the increased number of large platelets in any of the assessed organs, but in Myh9−/− mice a much stronger increase in BM reticulin fibers was present after 4 weeks of romiplostim treatment vs WT mice. These data further encourage short-term use of thrombopoietic agents in patients with MYH9-RDs; however, myelofibrosis has to be considered as a potential severe adverse effect during longer treatment. Reduction of GPIbIX/GPVI expression by romiplostim requires further studies.


2014 ◽  
Vol 59 (No. 10) ◽  
pp. 502-505 ◽  
Author(s):  
V. Ledecky ◽  
M. Hluchy ◽  
R. Freilichman ◽  
S. Hornak ◽  
D. Knazovicky

The aim of this study was to monitor short-term osteoarthrosis progress in relation to a recently introduced novel extracapsular method called the Tight Rope procedure and after Lateral Suture with nylon in cruciate-deficient dog stifle joints. Twelve dogs were included in the study. Treatment type was not randomised. Mediolateral radiographs from 12 stifle joint were evaluated preoperatively and six months after surgery. A modified scoring system for evaluation of osteoarthrotic changes was used. The initial osteoarthrotic score in the TightRope group ranged from three to six and in the Lateral Suture group from 0 to 11. In the TightRope group 66.6% of dogs had an osteoathrotic score difference of &le; 5 and 33.3% dogs had an osteoarthrotic score difference of &gt; 5. For the Lateral Suture group 50% of dogs had an osteoarthrotic score difference of &le; 5 and 50% dogs had an osteoarthrotic score difference of &gt; 5. The Wilcoxon signed rank test revealed a significant difference between preoperative and postoperative osteoarthrotic scores (P = 0.0038). No significant differences were noted between TightRope and Lateral Suture groups in terms of changes in mean radiographic osteoarthrotic score preoperatively and at the six-month postoperative end point. Both groups had numerically higher radiographic scores six months after surgery. &nbsp;


1998 ◽  
Vol 274 (3) ◽  
pp. R596-R603 ◽  
Author(s):  
Ian M. Chapman ◽  
Elizabeth A. Goble ◽  
Gary A. Wittert ◽  
John E. Morley ◽  
Michael Horowitz

To investigate the short-term effects of insulin on feeding, 14 fasting, young adults received 150-min euglycemic intravenous infusions of control (C), low-dose (LD, 0.8 mU ⋅ kg−1 ⋅ min−1), and high-dose (HD, 1.6 mU ⋅ kg−1 ⋅ min−1) insulin and ate freely from a buffet meal during the last 30 min. Steady-state preprandial plasma insulin concentrations were 5.9 ± 0.7 (C), 47 ± 2 (LD), and 95 ± 6 (HD) μU/ml and increased 56–59 μU/ml during the meal. No effect of treatment type on hunger or fullness ratings, duration of eating, or the weight, energy content (1,053 ± 95 kcal, C; 1,045 ± 101 kcal, LD; 1,066 ± 107 kcal, HD; P = 0.9), and composition of food eaten was observed. On a fourth study day, 12 of the subjects received an intravenous infusion of glucose only (Glc) that was identical to the glucose infusion on their HD insulin day. Mean venous glucose concentration was 9.3 ± 0.5 mmol [ P < 0.001 vs. C (5.3 ± 0.1), LD (5.2 ± 0.2), and HD (5.2 ± 0.2)], and plasma insulin increased to 45 ± 2.3 μU/ml at the start and 242 ± 36 μU/ml at the end of the meal. Energy intake during the meal was (∼15%) reduced (1,072 ± 97 kcal, C; 1,086 ± 102 kcal, LD; 1,088 ± 105 kcal, HD; 919 ± 115 kcal, Glc; P < 0.05 Glc vs. C, LD, and HD). Plasma insulin normally increases to ∼100 μU/ml after a mixed meal in lean subjects. Therefore, in the absence of altered blood glucose concentrations, physiological concentrations of insulin are unlikely to play a role in meal termination and the short-term control of appetite.


2000 ◽  
Vol 78 (6) ◽  
pp. 500-506 ◽  
Author(s):  
S Wang ◽  
G Wright ◽  
J Harrah ◽  
R Touchon ◽  
W McCumbee ◽  
...  

The effect of short-term exposure to homocysteine (Hcy) on the contractile characteristics of rat aortic tissue was assessed both in vitro and in vivo. The contractile response of Hcy-treated aortic rings in culture for 1 or 4 days was unchanged from control responses. By comparison, aortic rings from animals injected with Hcy showed marked attenuation of response compared with controls injected with saline, cysteine or methionine. The contractile response to K+ was decreased within 24 hours of Hcy injection, whereas the response to both K+ (-27%) and noradrenaline (-56%) was significantly decreased by 4 days. In contrast, the contractile response to phorbol-12,13-dibutyrate was not different between Hcy and control groups. Intimal rubbing completely restored the responsiveness of Hcy-treated tissue to K+ and noradrenaline. By comparison, L-NAME only partially restored contractile responsiveness, while the cyclooxygenase inhibitor indomethacin had no effect on contractile attenuation induced by Hcy. Western blot analysis showed a 2-fold increase of endothelial nitric oxide synthase (eNOS) and a 3-fold increase in inducible nitric oxide synthase (iNOS) protein expression in the aortic endothelial cells from Hcy-injected rats. The results indicate an early detectable effect of Hcy on the in vivo contractile properties of vascular smooth muscle. The effect is endothelium-mediated and may vary depending on the agonist studied. The mechanism is uncertain but appears to involve increased nitric oxide (NO) production. Finally, the data suggest that attenuation of contraction may not be due to a direct effect of Hcy but that the compound is modified or acts indirectly in vivo.Key words: nitric oxide, nitric oxide synthase, in vivo, smooth muscle.


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