scholarly journals Time lag between metamorphism and crystallization of anatectic granites (Córdoba, Argentina)

2020 ◽  
Vol 18 ◽  
pp. 1-14
Author(s):  
F.J. D´Eramo ◽  
J.J. Esteban ◽  
M. Demartis ◽  
E. Aragón ◽  
J.E. Coniglio ◽  
...  

SHRIMP and LA-ICP-MS analyses carried out on zircons from the Río de los Sauces granite revealed their metamorphic and igneous nature. The metamorphic zircons yielded an age of 537±4.8 (2σ)Ma that probably predates the onset of the anatexis during the Pampean orogeny. By contrast, the igneous zircons yielded a younger age of 529±6 (2σ)Ma and reflected its crystallization age. These data point to a short time lag of ca. 8Myr between the High Temperature (HT) metamorphic peak and the subsequent crystallization age of the granite. Concordia age of 534±3.8 (2σ)Ma, for both types of zircon populations, can be considered as the mean age of the Pampean HT metamorphism in the Sierras de Córdoba.

2014 ◽  
Vol 77 (5) ◽  
pp. 696-705 ◽  
Author(s):  
MATTHEW J. STASIEWICZ ◽  
NICOLE MARTIN ◽  
SHELLEY LAUE ◽  
YRJO T. GRÖHN ◽  
KATHRYN J. BOOR ◽  
...  

In a 2005 analysis of a potential bioterror attack on the food supply involving a botulinum toxin release into the milk supply, the authors recommended adopting a toxin inactivation step during milk processing. In response, some dairy processors increased the times and temperatures of pasteurization well above the legal minimum for high temperature, short time pasteurization (72°C for 15 s), with unknown implications for public health. The present study was conducted to determine whether an increase in high temperature, short time pasteurization temperature would affect the growth of Listeria monocytogenes, a potentially lethal foodborne pathogen normally eliminated with proper pasteurization but of concern when milk is contaminated postpasteurization. L. monocytogenes growth during refrigerated storage was higher in milk pasteurized at 82°C than in milk pasteurized at 72°C. Specifically, the time lag before exponential growth was decreased and the maximum population density was increased. The public health impact of this change in pasteurization was evaluated using a quantitative microbial risk assessment of deaths from listeriosis attributable to consumption of pasteurized fluid milk that was contaminated postprocessing. Conservative estimates of the effect of pasteurizing all fluid milk at 82°C rather than 72°C are that annual listeriosis deaths from consumption of this milk would increase from 18 to 670, a 38-fold increase (8.7- to 96-fold increase, 5th and 95th percentiles). These results exemplify a situation in which response to a rare bioterror threat may have the unintended consequence of putting the public at increased risk of a known, yet severe harm and illustrate the need for a paradigm shift toward multioutcome risk benefit analyses when proposing changes to established food safety practices.


1953 ◽  
Vol 20 (2) ◽  
pp. 156-176 ◽  
Author(s):  
Hazel Alexander ◽  
Constance Higginbottom

1. The numbers and species of micro-organisms surviving in commercial high-temperature short-time pasteurized milks sampled direct from the cooling section of the pasteurizer have been determined and compared with those in the corresponding raw milk and in the raw milk after low-temperature pasteurization in the laboratory.2. The geometric mean counts at 37° C. for twenty-five samples of raw, L.T. and H.T.S.T. pasteurized milks were 74,130, 1,740 and 3,200 per ml. respectively. The corresponding figures at 30° C. were 123,030, 7,080 and 8,510 per ml.3. The percentage destruction of the bacteria was slightly smaller at all four plants for the H.T.S.T. pasteurized milks than for the corresponding L.T. pasteurized milks. The mean percentage destruction for the L.T. pasteurized milks was 97·7% for bacteria growing at 37° C. and 94·3% for bacteria growing at 30° C. The corresponding figures for the H.T.S.T. pasteurized milks were 95·9 and 93·1%.


Alloy Digest ◽  
1966 ◽  
Vol 15 (11) ◽  

Abstract Ti-679 is a titanium high temperature alloy having an excellent combination of short-time strength, creep strength and stability to 900 F. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: Ti-48. Producer or source: Titanium Metals Corporation of America.


2020 ◽  
Vol 26 (1) ◽  
pp. 53-59 ◽  
Author(s):  
Jennifer M. Strahle ◽  
Rukayat Taiwo ◽  
Christine Averill ◽  
James Torner ◽  
Jordan I. Gewirtz ◽  
...  

OBJECTIVEIn patients with Chiari malformation type I (CM-I) and a syrinx who also have scoliosis, clinical and radiological predictors of curve regression after posterior fossa decompression are not well known. Prior reports indicate that age younger than 10 years and a curve magnitude < 35° are favorable predictors of curve regression following surgery. The aim of this study was to determine baseline radiological factors, including craniocervical junction alignment, that might predict curve stability or improvement after posterior fossa decompression.METHODSA large multicenter retrospective and prospective registry of pediatric patients with CM-I (tonsils ≥ 5 mm below the foramen magnum) and a syrinx (≥ 3 mm in width) was reviewed for clinical and radiological characteristics of CM-I, syrinx, and scoliosis (coronal curve ≥ 10°) in patients who underwent posterior fossa decompression and who also had follow-up imaging.RESULTSOf 825 patients with CM-I and a syrinx, 251 (30.4%) were noted to have scoliosis present at the time of diagnosis. Forty-one (16.3%) of these patients underwent posterior fossa decompression and had follow-up imaging to assess for scoliosis. Twenty-three patients (56%) were female, the mean age at time of CM-I decompression was 10.0 years, and the mean follow-up duration was 1.3 years. Nine patients (22%) had stable curves, 16 (39%) showed improvement (> 5°), and 16 (39%) displayed curve progression (> 5°) during the follow-up period. Younger age at the time of decompression was associated with improvement in curve magnitude; for those with curves of ≤ 35°, 17% of patients younger than 10 years of age had curve progression compared with 64% of those 10 years of age or older (p = 0.008). There was no difference by age for those with curves > 35°. Tonsil position, baseline syrinx dimensions, and change in syrinx size were not associated with the change in curve magnitude. There was no difference in progression after surgery in patients who were also treated with a brace compared to those who were not treated with a brace for scoliosis.CONCLUSIONSIn this cohort of patients with CM-I, a syrinx, and scoliosis, younger age at the time of decompression was associated with improvement in curve magnitude following surgery, especially in patients younger than 10 years of age with curves of ≤ 35°. Baseline tonsil position, syrinx dimensions, frontooccipital horn ratio, and craniocervical junction morphology were not associated with changes in curve magnitude after surgery.


2020 ◽  
Vol 328 ◽  
pp. 127126 ◽  
Author(s):  
Stefano Nebbia ◽  
Marzia Giribaldi ◽  
Laura Cavallarin ◽  
Enrico Bertino ◽  
Alessandra Coscia ◽  
...  

Life ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 114
Author(s):  
Diana Escuder-Vieco ◽  
Juan M. Rodríguez ◽  
Irene Espinosa-Martos ◽  
Nieves Corzo ◽  
Antonia Montilla ◽  
...  

Holder pasteurization (HoP; 62.5 °C, 30 min) is commonly used to ensure the microbiological safety of donor human milk (DHM) but diminishes its nutritional properties. A high-temperature short-time (HTST) system was designed as an alternative for human milk banks. The objective of this study was to evaluate the effect of this HTST system on different nutrients and the bile salt stimulated lipase (BSSL) activity of DHM. DHM was processed in the HTST system and by standard HoP. Macronutrients were measured with a mid-infrared analyzer. Lactose, glucose, myo-inositol, vitamins and lipids were assayed using chromatographic techniques. BSSL activity was determined using a kit. The duration of HTST treatment had a greater influence on the nutrient composition of DHM than did the tested temperature. The lactose concentration and the percentage of phospholipids and PUFAs were higher in HTST-treated than in raw DHM, while the fat concentration and the percentage of monoacylglycerides and SFAs were lower. Other nutrients did not change after HTST processing. The retained BSSL activity was higher after short HTST treatment than that following HoP. Overall, HTST treatment resulted in better preservation of the nutritional quality of DHM than HoP because relevant thermosensitive components (phospholipids, PUFAs, and BSSL) were less affected.


2021 ◽  
pp. 112067212110307
Author(s):  
Soner Guven

Purpose: To compare the prevalence, magnitude and type of corneal astigmatism between Turkish individuals and Syrian refugees. Material and methods: Data of patients scheduled for cataract surgery between January 2019 and 2020 were reviewed. The patients were randomly stratified according to their ethnicity (Turkish individuals or Syrian refugees). Keratometry was performed with the keratometer of IOLMaster 500. Quantitative analysis was performed using the power vector method (J0 and J45). The association between age and astigmatism in the two groups was explored. Results: The study included 4085 eyes of 2049 patients (3962 eyes of Turkish individuals and 123 eyes of Syrian refugees). The mean magnitude of corneal astigmatism, J0, J45 and prevalence of against the rule (ATR) astigmatism and with the rule (WTR) astigmatism were 1.01 D, 0.06, 0.01 D, 37.6% and 43.7% in Turkish individuals and 1.13 D, −0.02, 0.07 D, 46.3% and 37.4% in Syrian refugees, respectively. There were no significant differences according to age, sex, right/left eyes, corneal astigmatism magnitude, keratometric values, J0 and J45 ( p > 0.05) between the two groups. Below 40 years of age, the mean corneal astigmatism magnitude in Syrian refugees was significantly higher than that in Turkish individuals ( p = 0.037). At all ages, ATR astigmatism prevalence was higher in Syrian refugees than in Turkish individuals. ATR astigmatic shift began at a younger age in Syrian refugees ( p = 0.037). Age- and sex-adjusted analysis showed that J0 was significantly lower in Syrian refugees than in Turkish individuals ( p = 0.013). Conclusion: The prevalence and magnitude of ATR astigmatism were higher and onset earlier in Syrian refugees than in Turkish individuals.


2019 ◽  
Vol 49 (6) ◽  
pp. 1521-1539
Author(s):  
Yu-Kun Qian ◽  
Shiqiu Peng ◽  
Chang-Xia Liang

AbstractThe present study reconciles theoretical differences between the Lagrangian diffusivity and effective diffusivity in a transformed spatial coordinate based on the contours of a quasi-conservative tracer. In the transformed coordinate, any adiabatic stirring effect, such as shear-induced dispersion, is naturally isolated from diabatic cross-contour motions. Therefore, Lagrangian particle motions in the transformed coordinate obey a transformed zeroth-order stochastic (i.e., random walk) model with the diffusivity replaced by the effective diffusivity. Such a stochastic model becomes the theoretical foundation on which both diffusivities are exactly unified. In the absence of small-scale diffusion, particles do not disperse at all in the transformed contour coordinate. Besides, the corresponding Lagrangian autocorrelation becomes a delta function and is thus free from pronounced overshoot and negative lobe at short time lags that may be induced by either Rossby waves or mesoscale eddies; that is, particles decorrelate immediately and Lagrangian diffusivity is already asymptotic no matter how small the time lag is. The resulting instantaneous Lagrangian spreading rate is thus conceptually identical to the effective diffusivity that only measures the instantaneous irreversible mixing. In these regards, the present study provides a new look at particle dispersion in contour-based coordinates.


2016 ◽  
Vol 124 (4) ◽  
pp. 971-976 ◽  
Author(s):  
Kristin Huntoon ◽  
Tianxia Wu ◽  
J. Bradley Elder ◽  
John A. Butman ◽  
Emily Y. Chew ◽  
...  

OBJECT Peritumoral cysts are frequently associated with CNS hemangioblastomas and often underlie neurological morbidity and mortality. To determine their natural history and clinical impact, the authors prospectively analyzed hemangioblastoma-associated peritumoral cysts in patients with von Hippel-Lindau (VHL) disease. METHODS Patients with VHL disease who had 2 or more years of follow-up and who were enrolled in a prospective study at the National Institutes of Health were included. Serial prospectively acquired laboratory, genetic, imaging, and clinical data were analyzed. RESULTS One hundred thirty-two patients (of 225 in the VHL study with at least 2 years of follow-up) had peritumoral cysts that were followed for more than 2 years (total of 292 CNS peritumoral cysts). The mean age at study entrance was 37.4 ± 13.1 years ([mean ± SD], median 37.9, range 12.3–65.1 years). The mean follow-up was 7.0 ± 1.7 years (median 7.3, range 2.1–9.0 years). Over the study period, 121 of the 292 peritumoral cysts (41.4%) became symptomatic. Development of new cysts was associated with a larger number cysts at study enrollment (p = 0.002) and younger age (p < 0.0001). Cyst growth rate was associated with anatomical location (cerebellum cysts grew faster than spine and brainstem cysts; p = 0.0002 and p = 0.0008), younger age (< 35 years of age; p = 0.0006), and development of new neurological symptoms (p < 0.0001). Cyst size at symptom production depended on anatomical location (p < 0.0001; largest to smallest were found, successively, in the cerebellum, spinal cord, and brainstem). The most common location for peritumoral cysts was the cerebellum (184 cysts [63%]; p < 0.0001). CONCLUSIONS Peritumoral cysts frequently underlie symptom formation that requires surgical intervention in patients with VHL disease. Development of new cysts was associated with a larger number of cysts at study enrollment and younger age. Total peritumoral cyst burden was associated with germline partial deletion of the VHL gene.


1999 ◽  
Vol 62 (8) ◽  
pp. 861-866 ◽  
Author(s):  
PUNIDADAS PIYASENA ◽  
ROBIN C. McKELLAR

Mathematical models describing the thermal inactivation of γ-glutamyl transpeptidase (TP) and Listeria innocua in milk during high-temperature short-time (HTST) pasteurization were validated with data from TP, L. innocua, and L. monocytogenes trials in guar gum–milk. Holding tube times were determined for turbulent flow using water, and for laminar flow using a guar gum (0.27% wt/wt)–sucrose (5.3% wt/wt)–water mixture. Inactivation of TP and L. innocua was lower in a solution of guar gum (0.25% wt/wt) in whole milk than was predicted by models derived from studies with whole milk alone. Use of laminar flow timings improved model fit but did not completely account for the observed protective effect. L. monocytogenes survival was close to that predicted by the L. innocua model, although some protection was afforded this pathogen under laminar flow. Considerable intertrial variability was noted for L. monocytogenes. Risk analysis simulations using @RISK, a Lotus 1-2–3W add-in, were used to account for intertrial variability. Simulated log10 %reductions consistently underpredicted experimental L. monocytogenes survival (fail-safe), thus the L. innocua model derived in milk is suitable for estimating L. monocytogenes survival in viscous products. Increased thermal tolerance during laminar flow may be attributed to the protective effect of stabilizer.


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