1,086 research outputs found
The Effects of Night-time Temperatures on Physiological and Biochemical Traits in Rice
High nighttime temperatures impair rice yield. Additionally, heat stress periods have increased during the last years in the rice areas of the tropics. The aim of this study was to physiologically characterize six genotypes of rice (a commercial cultivar (ʻF60ʼ) and five selected lines (ʻIR 1561ʼ, ʻFLO 2764ʼ, ʻLV447-1ʼ, ʻCT19021ʼ, and ʻLV1401ʼ) subjected to two nighttime temperatures (24 and 30 °C), based on different physiological traits. When the collar formed on leaf 6 of the main stem, one group of six plants in each genotype was subjected to 30 °C from 18:00 to 24:00 hours for eight days, while the other group remained at 24 °C. Differences were found in the interaction between genotype and nighttime temperatures, where a high night temperature reduced leaf photosynthesis by approximately 50% in all genotypes compared to the controls (20 µmol vs. 10 µmol CO2 m-2 s-1, respectively). In general, higher plant respiration was also observed in almost all genotypes when the plants were exposed to 30 °C. However, rice plants of the genotype ʻF60ʼ showed a constant respiration under two different night temperatures. A high nighttime temperature increased the electrolyte leakage and malondialdehyde content only in the ʻLV1401ʼ plants. Plant growth and Fv/Fm ratio were separately conditioned by the night temperature or the genotype factor. A lower total plant dry weight was found at 30 °C (620.36 mg) than in rice plants exposed to 24 °C (254.16 mg). The Fv/Fm ratio was slightly diminished at a high nighttime temperature. These results suggest that physiological variables, such as leaf photosynthesis, plant respiration, malondialdehyde content and leaf photosynthetic pigments, can be considered markers for characterizing tolerant genotypes in earlier growth phases during plant breeding programs
A Study to Assess the Relationship between Attention Deficit Hyperactivity Disorder and Obstructive Sleep Apnea in Adults
The association between obstructive sleep apnea (OSA) and attention deficit hyperactivity disorder (ADHD) is well-established in children. However, there is a paucity of literature regarding this association in adults. The aim of this study was to determine if ADHD is more common in adult patients with OSA. All patients referred to a sleep center for sleep evaluation were administered the Adult ADHD Self-Report Scale and diagnostic polysomnogram. The ADHD screen is considered positive if 4 of 6 questions in part A of the screening questionnaire were answered abnormally. The study population consisted of 194 participants, predominantly male (62%), Caucasian (54%), and Hispanic (44%). OSA was identified in 160 (83%) of participants, with 116 (60%) having moderate to severe OSA. The ADHD screen was positive in 37 (19%) of participants. There was no significant association between the severity of OSA and presence of ADHD symptoms. Patients with OSA who screened positive for ADHD had higher Epworth Sleepiness Scale scores than those that did not. These data suggest that ADHD is more prevalent in patients with OSA, but do not demonstrate a relationship between OSA severity and ADHD symptoms. Interestingly, sleepiness is more prominent in patients with ADHD
Decrease in antibiotic resistance of Streptococcus pneumoniae between 2003 and 2009 in France and changes in serotype distribution: Ongoing survey of the French Pneumococcus Surveillance Network
Background:
The French regional pneumococcal observatories (ORP) network was created in 1995, it participates to the close monitoring of the trends in antimicrobial resistance and serotype distribution with the National Reference Centre for Pneumococci (NRCP) and the Institut de Veille Sanitaire (InVS). The aim of this survey was to assess the antibiotic resistance and the distribution of vaccine and non-vaccine serotypes in invasive pneumococcal disease (IPD) in adults and children as well in otitis in children in France in 2009.
Methods:
Antimicrobial susceptibility testing was performed on 5,194 isolates of S. pneumoniae recovered from cerebrospinal fluid (CSF), blood, middle ear fluid (MEF) and pleural fluid during the year 2009 by the 23 ORP. MICs of penicillin (P), amoxicillin (AMX) and cefotaxime (CTX) were determined by the agar dilution method and interpreted according to the Antibiotics Comity of the French Society of Microbiology breakpoints. Serotyping was performed at the NRCP with serotype-specific antisera, by latex agglutination test.
Results:
Results of susceptibility between 2003 and 2009 to P are presented in Table 1. The pneumococci with decreased susceptibility to penicillin G (PDSP) decreased significantly in all types of samples except for MEF’s isolates in children between 2007 and 2009. In the global population, the percentage of I+R (2003 vs 2009) decreased significantly for AMX (30.3% versus 9.6%) and for CTX (18.2% versus 10.5%). Strains highly resistant (MIC > 2 mg/L) remained rare: 0.4%, 1.1% and 0.2% for P, AMX and CTX respectively. The most frequent capsular types in CSF were 3, 7F, 19A, 6C, 23B for adults and 7F, 19A, 3, 33F and 15B for children. Serotypes included in the PCV-7 and PCV-13 vaccine accounted in children for 4% and 51% respectively and in adults for 12% and 48% respectively. By contrast, the serotype 19A remained highly predominant (80%) among MEF isolates.
Conclusions:
We observed a significant decrease of PDSP between 2003 and 2009 (50.2 to 33.0%). The decrease coincided with the introduction of PCV7 and with a general reduction in levels of antibiotic consumption in France. This continuous survey is necessary to underline modification in serotype distribution in France after PVC13 introduction (June 2010)
Detecting and quantifying methane emissions from oil and gas production: algorithm development with ground-truth calibration based on Sentinel-2 satellite imagery
Sentinel-2 satellite imagery has been shown by studies to be
capable of detecting and quantifying methane emissions from oil and gas
production. However, current methods lack performance calibration with
ground-truth testing. This study developed a multi-band–multi-pass–multi-comparison-date methane retrieval algorithm that enhances Sentinel-2 sensitivity to methane plumes. The method was calibrated
using data from a large-scale controlled-release test in Ehrenberg, Arizona,
in fall 2021, with three algorithm parameters tuned based on the true
emission rates. Tuned parameters are the pixel-level concentration upper-bound threshold during extreme value removal, the number of comparison
dates, and the pixel-level methane concentration percentage threshold when
determining the spatial extent of a plume. We found that a low value of the
upper-bound threshold during extreme value removal can result in false
negatives. A high number of comparison dates helps enhance the algorithm
sensitivity to the plumes in the target date, but values in excess of
12 d are neither necessary nor computationally efficient. A high percentage
threshold when determining the spatial extent of a plume helps enhance the
quantification accuracy, but it may harm the yes/no detection accuracy. We
found that there is a trade-off between quantification accuracy and
detection accuracy. In a scenario with the highest quantification accuracy,
we achieved the lowest quantification error and had zero false-positive
detections; however, the algorithm missed three true plumes, which reduced the
yes/no detection accuracy. In contrast, all of the true plumes were
detected in the highest detection accuracy scenario, but the emission rate
quantification had higher errors. We illustrated a two-step method that
updates the emission rate estimates in an interim step, which improves
quantification accuracy while keeping high yes/no detection accuracy. We
also validated the algorithm's ability to detect true positives and true
negatives in two application studies.</p
FGF4 retrogene on CFA12 is responsible for chondrodystrophy and intervertebral disc disease in dogs.
Chondrodystrophy in dogs is defined by dysplastic, shortened long bones and premature degeneration and calcification of intervertebral discs. Independent genome-wide association analyses for skeletal dysplasia (short limbs) within a single breed (PBonferroni = 0.01) and intervertebral disc disease (IVDD) across breeds (PBonferroni = 4.0 × 10-10) both identified a significant association to the same region on CFA12. Whole genome sequencing identified a highly expressed FGF4 retrogene within this shared region. The FGF4 retrogene segregated with limb length and had an odds ratio of 51.23 (95% CI = 46.69, 56.20) for IVDD. Long bone length in dogs is a unique example of multiple disease-causing retrocopies of the same parental gene in a mammalian species. FGF signaling abnormalities have been associated with skeletal dysplasia in humans, and our findings present opportunities for both selective elimination of a medically and financially devastating disease in dogs and further understanding of the ever-growing complexity of retrogene biology
Treatment of von Willebrand disease
Summary. von Willebrand disease is the most frequent of inherited bleeding disorders (1:100 affected individuals in the general population). The aim of treatment is to correct the dual defects of haemostasis, i.e., abnormal coagulation expressed by low levels of factor VIII and abnormal platelet adhesion expressed by a prolonged bleeding time. There are two main options available for the management of von Willebrand disease: desmopressin and transfusion therapy with blood products. Desmopressin is the treatment of choice in patients with type 1 von Willebrand disease, who account for approximately 80% of cases. This pharmacological compound raises endogenous factor VIII and von Willebrand factors and thereby corrects the intrinsic coagulation defect and the prolonged bleeding time in most type 1 patients. In type 3 and in the majority of type 2 patients desmopressin is not effective, and it is necessary to resort to plasma concentrates containing factor VIII and von Willebrand factor. Treated with virucidal methods, these concentrates are effective and currently safe, but the bleeding time defect is not always corrected by them. Platelet concentrates or desmopressin can be used as adjunctive treatments when poor correction of the bleeding time after concentrates is associated with continued bleeding
Helicobacter pullorum cytolethal distending toxin targets vinculin and cortactin and triggers formation of lamellipodia in intestinal epithelial cells
Helicobacter pullorum, a bacterium initially isolated from poultry, has been associated with human digestive
disorders. However, the factor responsible for its cytopathogenic effects on epithelial cells has not been formally
identified. The cytopathogenic alterations induced by several human and avian H. pullorum strains were investigated
on human intestinal epithelial cell lines. Moreover, the effects of the cytolethal distending toxin
(CDT) were evaluated first by using a wild-type strain and its corresponding cdtB isogenic mutant and second
by delivering the active CdtB subunit of the CDT directly into the cells. All of the H. pullorum strains induced
cellular distending phenotype, actin cytoskeleton remodeling, and G2/M cell cycle arrest. These effects were dependent
on the CDT, as they were (1) not observed in response to a cdtB isogenic mutant strain and (2) present
in cells expressing CdtB. CdtB also induced an atypical delocalization of vinculin from focal adhesions to the
perinuclear region, formation of cortical actin-rich large lamellipodia with an upregulation of cortactin, and
decreased cellular adherence. In conclusion, the CDT of H. pullorum is responsible for major cytopathogenic
effects in vitro, confirming its role as a main virulence factor of this emerging human pathogen.This work was supported by the Institut national de la santé et de la recherche médicale, the University Bordeaux Segalen, the Conseil Régional d’Aquitaine (grants 20030304002FA and 20040305003 FA), the Société Nationale Française de Gastroentérologie, the European Union (FEDER no. 2003227
Dephasing-induced diffusive transport in anisotropic Heisenberg model
We study transport properties of anisotropic Heisenberg model in a disordered
magnetic field experiencing dephasing due to external degrees of freedom. In
the absence of dephasing the model can display, depending on parameter values,
the whole range of possible transport regimes: ideal ballistic conduction,
diffusive, or ideal insulating behavior. We show that the presence of dephasing
induces normal diffusive transport in a wide range of parameters. We also
analyze the dependence of spin conductivity on the dephasing strength. In
addition, by analyzing the decay of spin-spin correlation function we discover
a presence of long-range order for finite chain sizes. All our results for a
one-dimensional spin chain at infinite temperature can be equivalently
rephrased for strongly-interacting disordered spinless fermions.Comment: 15 pages, 9 PS figure
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