A semi-empirical representation of the temporal variation of total greenhouse gas levels expressed as equivalent levels of carbon dioxide

Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).In order to examine the underlying longer-term trends in greenhouse gases, that are driven for example by anthropogenic emissions or climate change, it is useful to remove the recurring effects of natural cycles and oscillations on the sources and/or sinks of those gases that have strong biological (e.g., CO2, CH4, N2O) and/or photochemical (e.g. CH4) influences on their global atmospheric cycles. We use global observations to calculate monthly estimates of greenhouse gas levels expressed as CO2 equivalents, and then fit these estimates to a semi-empirical model that includes the natural seasonal, QBO, and ENSO variations, as well as a second order polynomial expressing longer-term variations. We find that this model provides a reasonably accurate fit to the observation-based monthly data. We also show that this semiempirical model has some predictive capability; that is it can be used to provide a reasonably reliable estimate of CO2 equivalents at the current time using validated observations that lag real time by a few to several months.This study received support from the MIT Joint Program on the Science and Policy of Global Change, which is funded by a consortium of government, industry and foundation sponsors

Simulating broken PT\cal PT-symmetric Hamiltonian systems by weak measurement

By embedding a $\cal PT$-symmetric (pseudo-Hermitian) system into a large Hermitian one, we disclose the relations between $\cal{PT}$-symmetric Hamiltonians and weak measurement theory. We show that the amplification effect in weak measurement on a conventional quantum system can be used to effectively simulate a local broken $\cal PT$-symmetric Hamiltonian system, with the pre-selected state in the $\cal PT$-symmetric Hamiltonian system and its post-selected state resident in the dilated Hamiltonian system.Comment: 4 pages; with Supplemental Materia

Flexible parylene-based 3-D coiled cable

Prosthesis systems require reliable and flexible connecting cables from the sensing/stimulating electrode sites to processing circuitries. However, the limitations on the fabrication materials and processes restrict the cables' ability to stretch, resulting in breakage and failure of the implanted cabled device. Thus, a microfabricated and fully implantable 3-D parylene coiled cable for prosthesis application is presented. Compared to traditional flexible cables, this parylene coiled structure is able to be stretched by 100% of its original length and is also long-term biocompatible. In addition, the cable structure can be heat-formed in a mold to match muscle curvature and sharp turns in testing subjects and can also be directly integrated with flexible multi-electrodes arrays and neural probes

Development and application of an UHPLC-MS/MS method for the simultaneous determination of 17 steroidal hormones in equine serum

A new, fast and simple analytical method that is able to identify and quantify simultaneously 17 steroid hormones and metabolites (Pregnenolone, 17-OH-Pregnenolone, Progesterone, 17-OH Progesterone, Androsterone, Androstenedione, DHEA, DHEAS, Testosterone, Cortisol, Corticosterone, Aldosterone, 11-Deoxycortisol, 11-Deoxycorticosterone, Dihydrotestosterone, Estrone, Estradiol) has been developed in equine serum using the UHPLC-MS/MS technique. 400 μL of sample were deproteinized with 1000 µl of acetonitrile, evaporated, restored with 50 µl of a solution of 25% methanol and injected in UHPLC-MS/MS triple quadrupole. The recovery percentage obtained by spiking the matrix at two different concentrations with a standard mixture of steroid hormones was in all cases higher than 85.60 % and with the percentage of coefficient of variation (CV) lower than 8.37%. The range of the correlation coefficients of the calibration curves of the analyzed compounds was 0.9922–0.9986, and the limits of detection (LODs) and limits of quantification (LOQs) were in the range of 0.002–2 ng ml-1 and 0.0055-5.5 ng ml-1, respectively. The detected LOQ for testosterone (i.e. 50 pg ml-1) is two-fold lower with respect to its threshold admitted in geldings plasma (100 pg ml-1 free testosterone). The high sensitivity and the quantitative aspect of the method permitted to detect most of steroids in equine serum. Once validated, the method was used to quantify 17 steroid hormones in mare, stallion and gelding serum samples. The main steroids detected were corticosterone (range 37.25-51.26 ng ml-1) and cortisol (range 32.57-52.24 ng ml-1), followed by 17-OH-pregnenolone, dihydrotestosterone and pregnenolone

Refined Analytic Torsion as an Element of the Determinant Line

We construct a canonical element, called the refined analytic torsion, of the determinant line of the cohomology of a closed oriented odd-dimensional manifold M with coefficients in a flat complex vector bundle E. We compute the Ray-Singer norm of the refined analytic torsion. In particular, if there exists a flat Hermitian metric on E, we show that this norm is equal to 1. We prove a duality theorem, establishing a relationship between the refined analytic torsions corresponding to a flat connection and its dual.Comment: A sign in the definition (4.2) is changed (we are grateful to Guangxiang Su for this correction). Some minor misprints are also correcte

HDAC 1 and 6 modulate cell invasion and migration in clear cell renal cell carcinoma

Indexación: Web of ScienceBackground: Class I histone deacetylases (HDACs) have been reported to be overexpressed in clear cell renal cell carcinoma (ccRCC), whereas the expression of class II HDACs is unknown. Methods: Four isogenic cell lines C2/C2VHL and 786-O/786-OVHL with differential VHL expression are used in our studies. Cobalt chloride is used to mimic hypoxia in vitro. HIF-2 alpha knockdowns in C2 and 786-O cells is used to evaluate the effect on HDAC 1 expression and activity. Invasion and migration assays are used to investigate the role of HDAC 1 and HDAC 6 expression in ccRCC cells. Comparisons are made between experimental groups using the paired T-test, the two-sample Student's T-test or one-way ANOVA, as appropriate. ccRCC and the TCGA dataset are used to observe the clinical correlation between HDAC 1 and HDAC 6 overexpression and overall and progression free survival. Results: Our analysis of tumor and matched non-tumor tissues from radical nephrectomies showed overexpression of class I and II HDACs (HDAC6 only in a subset of patients). In vitro, both HDAC1 and HDAC6 over-expression increased cell invasion and motility, respectively, in ccRCC cells. HDAC1 regulated invasiveness by increasing matrix metalloproteinase (MMP) expression. Furthermore, hypoxia stimulation in VHL-reconstituted cell lines increased HIF isoforms and HDAC1 expression. Presence of hypoxia response elements in the HDAC1 promoter along with chromatin immunoprecipitation data suggests that HIF-2 alpha is a transcriptional regulator of HDAC1 gene. Conversely, HDAC6 and estrogen receptor alpha (ER alpha) were co-localized in cytoplasm of ccRCC cells and HDAC6 enhanced cell motility by decreasing acetylated alpha-tubulin expression, and this biological effect was attenuated by either biochemical or pharmacological inhibition. Finally, analysis of human ccRCC specimens revealed positive correlation between HIF isoforms and HDAC. HDAC1 mRNA upregulation was associated with worse overall survival in the TCGA dataset. Conclusions: Taking together, these results suggest that HDAC1 and HDAC6 may play a role in ccRCC biology and could represent rational therapeutic targets.http://bmccancer.biomedcentral.com/articles/10.1186/s12885-016-2604-

Attributable healthcare utilization and cost of pneumonia due to drug-resistant streptococcus pneumonia: a cost analysis

Background: The burden of disease due to S. pneumoniae (pneumococcus), particularly pneumonia, remains high despite the widespread use of vaccines. Drug resistant strains complicate clinical treatment and may increase costs. We estimated the annual burden and incremental costs attributable to antibiotic resistance in pneumococcal pneumonia. Methods: We derived estimates of healthcare utilization and cost (in 2012 dollars) attributable to penicillin, erythromycin and fluoroquinolone resistance by taking the estimate of disease burden from a previously described decision tree model of pneumococcal pneumonia in the U.S. We analyzed model outputs assuming only the existence of susceptible strains and calculating the resulting differences in cost and utilization. We modeled the cost of resistance from delayed resolution of illness and the resulting additional health services. Results: Our model estimated that non-susceptibility to penicillin, erythromycin and fluoroquinolones directly caused 32,398 additional outpatient visits and 19,336 hospitalizations for pneumococcal pneumonia. The incremental cost of antibiotic resistance was estimated to account for 4% ($91 million) of direct medical costs and 5$233 million) of total costs including work and productivity loss. Most of the incremental medical cost ($82 million) was related to hospitalizations resulting from erythromycin non-susceptibility. Among patients under age 18 years, erythromycin non-susceptibility was estimated to cause 17$38 million in costs, or 39% of pneumococcal pneumonia costs attributable to resistance. Conclusions: We estimate that antibiotic resistance in pneumococcal pneumonia leads to substantial healthcare utilization and cost, with more than one-third driven by macrolide resistance in children. With 5% of total pneumococcal costs directly attributable to resistance, strategies to reduce antibiotic resistance or improve antibiotic selection could lead to substantial savings

Plasticity of cerebellar Purkinje cells in behavioral training of body balance control

Neural responses to sensory inputs caused by self-generated movements (reafference) and external passive stimulation (exafference) differ in various brain regions. The ability to differentiate such sensory information can lead to movement execution with better accuracy. However, how sensory responses are adjusted in regard to this distinguishability during motor learning is still poorly understood. The cerebellum has been hypothesized to analyze the functional significance of sensory information during motor learning, and is thought to be a key region of reafference computation in the vestibular system. In this study, we investigated Purkinje cell (PC) spike trains as cerebellar cortical output when rats learned to balance on a suspended dowel. Rats progressively reduced the amplitude of body swing and made fewer foot slips during a 5-min balancing task. Both PC simple (SSs; 17 of 26) and complex spikes (CSs; 7 of 12) were found to code initially on the angle of the heads with respect to a fixed reference. Using periods with comparable degrees of movement, we found that such SS coding of information in most PCs (10 of 17) decreased rapidly during balance learning. In response to unexpected perturbations and under anesthesia, SS coding capability of these PCs recovered. By plotting SS and CS firing frequencies over 15-s time windows in double-logarithmic plots, a negative correlation between SS and CS was found in awake, but not anesthetized, rats. PCs with prominent SS coding attenuation during motor learning showed weaker SS-CS correlation. Hence, we demonstrate that neural plasticity for filtering out sensory reafference from active motion occurs in the cerebellar cortex in rats during balance learning. SS-CS interaction may contribute to this rapid plasticity as a form of receptive field plasticity in the cerebellar cortex between two receptive maps of sensory inputs from the external world and of efference copies from the will center for volitional movements