Dependences of the Casimir-Polder interaction between an atom and a cavity wall on atomic and material properties

The Casimir-Polder and van der Waals interactions between an atom and a flat cavity wall are investigated under the influence of real conditions including the dynamic polarizability of the atom, actual conductivity of the wall material and nonzero temperature of the wall. The cases of different atoms near metal and dielectric walls are considered. It is shown that to obtain accurate results for the atom-wall interaction at short separations, one should use the complete tabulated optical data for the complex refractive index of the wall material and the accurate dynamic polarizability of an atom. At relatively large separations in the case of a metal wall, one may use the plasma model dielectric function to describe the dielectric properties of wall material. The obtained results are important for the theoretical interpretation of experiments on quantum reflection and Bose-Einstein condensation.Comment: 5 pages, 1 figure, iopart.cls is used, to appear in J. Phys. A (special issue: Proceedings of QFEXT05, Barcelona, Sept. 5-9, 2005

Selective decrease of mRNAs encoding plasma membrane calcium pump isoforms 2 and 3 in rat kidney

Selective decrease of mRNAs encoding plasma membrane calcium pump isoforms 2 and 3 in rat kidney.BackgroundAlthough the existence of multiple isoforms of plasma membrane calcium ATPase (PMCA) is now well documented, their biological functions are not yet known. In this study, we set out to investigate the potential role of PMCA isoforms, previously identified in renal cortical tissue, in tubular reabsorption of calcium (Ca2+).MethodsWith use of reverse transcription-polymerase chain reaction analysis, we determined levels of mRNAs encoding isoforms of PMCA1 through PMCA4 in renal cortex, liver, and brain of rats with hypercalciuria induced by feeding with a low-phosphate diet (LPD) as compared with Ca2+-retaining rats that were fed a high-phosphate diet (HPD).ResultsWe observed that in hypercalciuric LPD-fed rats, the mRNAs encoding isoforms PMCA2b and PMCA3(a + c) are significantly lower (Δ approximately -50%) than in HPD-fed hypocalciuric rats, whereas no changes in mRNAs encoding isoforms PMCA1b and PMCA4 were observed, and mRNA encoding calbindin 28 kDa was increased. On the other hand, the content of mRNAs encoding PMCA2b and PMCA3(a + c) in liver and brain, respectively, was not changed.ConclusionThese findings are evidence that expression of PMCA isoforms in the kidney can be selectively modulated in response to pathophysiologic stimuli. The association of a decrease in mRNA encoding PMCA2b and PMCA3(a + c) with hypercalciuria suggests that the two PMCA isoforms may be operant in tubular reabsorption of Ca2+ and its regulation

Presentación: A educación social como relato histórico de amplas avenidas pedagóxicas e sociais

As primeiras referencias documentadas sobre a Educación Social sitúanse cronoloxicamente nos inicios do século XIX. Dende entón, en converxencia coa crecente relevancia que irán adquirindo as Ciencias Sociais e a súa énfase na consideración da educación como un feito ou unha práctica social, suscitará novas lecturas do quefacer educativo; en particular os que aspiran a dar resposta ás múltiples necesidades que emerxen da vida cotiá, como son a atención á infancia e á mocidade en situación de inadaptación e risco social, a educación das persoas adultas, ou a animación sociocultural. En todo caso, sen que poidan obviarse os importantes avances que se rexistran nas Ciencias da Educación (en particular da Pedagoxía Social), na acción-Intervención social e o Traballo Social. A democratización das sociedades, o auxe das políticas educativas, sociais e culturais, en conxunción co desenvolvemento da formación académica nas Universidades, xunto coa incesante profesionalización destes ámbitos, marcará decisivamente o seu percorrido histórico en Europa e no mundo. Así se reflicte neste monográfico ao salientar o importante recoñecemento que están adquirindo a Pedagoxía Social e a Educación Social no espazo iberoamericano, con alusións explícitas ás realidades galega, española, portuguesa e latinoamericana, focalizando a mirada histórica en catro dimensións principais: a contextual, a teórico-epistemolóxica, a formativa-académica e a profesional.info:eu-repo/semantics/publishedVersio

Value of scintigraphy in chronic peritoneal dialysis patients

Value of scintigraphy in chronic peritoneal dialysis patients.BackgroundA variety of factors can adversely impact chronic peritoneal dialysis (CPD) as an effective renal replacement therapy for patients with end-stage renal disease. These factors include peritonitis, poor clearances, loss of ultrafiltration, and a variety of anatomic problems, such as hernias, peritoneal fluid leaks, loculations, and catheter-related problems caused by omental blockage. This study reviews our experience with peritoneal scintigraphy for the evaluation of some of these difficulties.MethodsFrom 1991 to 1996, 50 peritoneal scintigraphy scans were obtained in 48 CPD patients. Indications for scintigraphy were evaluated, and the patients were placed into four groups: group I, abdominal wall swelling; group II, inguinal or genital swelling; group III, pleural fluid; and group IV, poor drainage and/or poor ultrafiltration. A peritoneal scintigraphy protocol was established and the radiotracer isotope that was used was 2.0 mCi of 99mtechnetium sulfur colloid placed in two liters of 2.5% dextrose peritoneal dialysis solution.ResultsTen scans were obtained to study abdominal wall swelling, with seven scans demonstrating leaks; six of these episodes improved with low-volume exchanges. Twenty scans were obtained to evaluate inguinal or genital swelling, and 10 of these had scintigraphic evidence for an inguinal hernia leak (9 of these were surgically corrected). One of four scans obtained to evaluate a pleural fluid collection demonstrated a peritoneal-pleural leak that corrected with a temporary discontinuation of CPD. Sixteen scans were obtained to assess poor drainage and/or ultrafiltration. Five of these scans demonstrated peritoneal location, and all of these patients required transfer to hemodialysis. The other 11 scans were normal; four patients underwent omentectomies, allowing three patients to continue with CPD.ConclusionPeritoneal scintigraphy is useful in the evaluation and assessment of CPD patients who develop anatomical problems (such as anterior abdominal, pleural-peritoneal, inguinal, and genital leaks) and problems with ultrafiltration and/or drainage

Dependences of the van der Waals atom-wall interaction on atomic and material properties

The 1%-accurate calculations of the van der Waals interaction between an atom and a cavity wall are performed in the separation region from 3 nm to 150 nm. The cases of metastable He${}^{\ast}$ and Na atoms near the metal, semiconductor or dielectric walls are considered. Different approximations to the description of wall material and atomic dynamic polarizability are carefully compared. The smooth transition to the Casimir-Polder interaction is verified. It is shown that to obtain accurate results for the atom-wall van der Waals interaction at shortest separations with an error less than 1% one should use the complete optical tabulated data for the complex refraction index of the wall material and the accurate dynamic polarizability of an atom. The obtained results may be useful for the theoretical interpretation of recent experiments on quantum reflection and Bose-Einstein condensation of ultracold atoms on or near surfaces of different nature.Comment: 14 pages, 5 figures, 3 tables, accepted for publication in Phys. Rev.

Acoustic assessment and distribution of the main pelagic fish species in ICES Subdivision 9a South during the ECOCADIZ 2020-07 Spanish survey (August 2020)

The present working document summarises the main results obtained from the ECOCADIZ 2020-07 Spanish (pelagic ecosystem-) acoustic-trawl survey conducted by IEO between 01st and 14th August 2020 in the Portuguese and Spanish shelf waters (20-200 m isobaths) off the Gulf of Cadiz (GoC) onboard the R/V Miguel Oliver. The 21 foreseen acoustic transects were sampled. A total of 26 valid fishing hauls were carried out for echo-trace ground-truthing purposes. Four additional night trawls were conducted to collect anchovy hydrated females (DEPM-adult ad hoc sampling). Chub mackerel was the most frequent captured species in the fishing hauls, followed by mackerel, anchovy, horse mackerel, bogue, sardine, blue jack mackerel and Mediterranean horse mackerel. Round sardinella, longspine snipefish, Atlantic pomfret and transparent goby showed a very low occurrence, whereas the occurrence of boarfish and pearlside was incidental. Chub mackerel, anchovy and sardine showed the highest yields in these hauls. The estimate of total NASC allocated to the “pelagic fish species assemblage” has shown a slight decrease in relation to the historical records in 2018 and 2019, mainly caused by the regional decrease in Spanish waters. However, both total and regional estimates are still above their respective historical averages. Such estimates are the result of the relatively high acoustic contributions of anchovy, sardine (both mainly in Spanish waters), and chub mackerel (in Portuguese waters). GoC anchovy was widely distributed in the surveyed area, showing the highest densities between Cape Santa Maria and Bay of Cadiz. Anchovy acoustic estimates in summer 2020 were of 5153 million fish and 44 877 tones, with the bulk of the population occurring in the Spanish waters. The population was composed by fishes not older than 2 years, with age-0 fish contributing 75% of the total population. The largest (and oldest) fish were distributed in the westernmost waters and the smallest (and youngest) ones concentrated in the surroundings of the Guadalquivir river mouth and adjacent shallow waters. The current biomass estimate becomes in the second historical maximum within the time-series. GoC sardine distributed almost all over the surveyed area (avoiding the Spanish easternmost waters), but was mainly concentrated between west Cape Santa Maria and the Bay of Cadiz, especially in the Spanish central waters of the Gulf, where numerous dense mid-water schools were recorded in the coastal fringe (20-40 m depth). The estimates of sardine abundance and biomass in summer 2020 were 1923 million fish and 50 721 t, estimates close to the historical average, but lower than the values estimated last year and the most recent maxima reached in 2018. Although up to 5-year olds were recorded in the population, age-0 juveniles accounted for 71% of the total numbers, mainly occurring in relatively shallow waters along the coastal fringe comprised between Tinto-Odiel river mouth and the Bay of Cadiz. Chub mackerel was widely distributed in the surveyed area, mainly in the central and western shelf waters, although the highest densities occurred in the western Algarve. A total of 32 854 t and 448 million fish were estimated for Chub mackerel, estimates similar to the most recent ones and very close to the time-series average. Age-0 and age-1 groups were the dominant age groups and mainly occurring in the Portuguese waters. The oldest fish (3-5 years) occurred almost exclusively in Spanish water

Acoustic assessment and distribution of the main pelagic fish species in ICES Subdivision 9a South during the ECOCADIZ-RECLUTAS 2020-10 Spanish survey (October 2020)

The present working document summarises the main results obtained from the ECOCADIZ-RECLUTAS 2020-10 Spanish (pelagic ecosystem-) acoustic-trawl survey conducted by IEO between 02nd and 21st October 2020 in the Portuguese and Spanish shelf waters (20-200 m isobaths) off the Gulf of Cadiz (GoC) onboard the R/V Ramón Margalef. The survey’s main objective is the acoustic assessment of anchovy and sardine juveniles (age 0 fish) in the GoC recruitment areas. The 21 foreseen acoustic transects were sampled. A total of 22 valid fishing hauls were carried out for echo-trace ground-truthing purposes. Chub mackerel, anchovy, mackerel and sardine were the most frequent captured species in the fishing hauls, followed by bogue, horse mackerel, Mediterranean horse mackerel and blue jack mackerel. Boarfish, longspine snipefish and pearlside showed an incidental occurrence in the hauls performed in the surveyed area. Sardine, anchovy, chub mackerel and mackerel showed the highest yields. Total and regional estimates of total NASC allocated to the “pelagic fish species assemblage” in this survey become the historical records in their time-series. Such estimates are the result of the relatively high acoustic contributions of sardine (both in Portuguese and Spanish waters), anchovy (in Spanish waters), and chub mackerel (in Portuguese waters). GoC anchovy was widely distributed in the surveyed area, although higher densities were recorded between east of Cape Santa Maria and Bay of Cadiz. Anchovy acoustic estimates in autumn 2020, 36 070 t and 3197 million fish, showed a decrease in relation to the historical peak recorded the last year, but they were either close (abundance) or even higher (biomass) than the time-series average. The population was composed by fishes not older than 3 years. As usual, the bulk of the population, including juveniles, was located in Spanish waters. Age-0 anchovies accounted for 75% (2385 million) and 58% (21 060 t) of the total estimated abundance and biomass, respectively. Age-0 estimates experienced a similar decreasing trend than the one showed by the whole population in relation to the historical peak recorded the year before, but with values close to the time-series average. GoC sardine experienced a huge increase in autumn 2020, rising up to its time-series maximum and yielding 208 400 t and 5451 million fish, with similar regional contributions to the population and with the juveniles being located in the Spanish coastal waters. Age-6 group was the oldest age group in the population, although the occurrence of fishes older than 4 years was incidental. The population was mainly composed by fishes belonging to the age-0 to age-2 groups. Juvenile sardines (age-0 group) were the dominant group, accounting for 45% and 24% of the total abundance (2454 million) and biomass (49 259 t), respectively. This age-group also recorded its historical maximum in 2020. Chub mackerel estimates were of 22 918 t and 295 million fish, representing a slight decrease compared with the last year, but still above the time-series average. The population was composed by fishes not older than 3 years, with the age-1 group being the dominant one (73%, 216 million, and 75%, 17 082 t, of the total abundance and biomass). Age-0 fish was the second most important age group in the estimated population (17%, 51 million fish, and 12%, 2759 t, of the total abundance and biomass estimates). The bulk of the age-0 (73%) and age-1 groups (74%) was recorded in the Portuguese water

A theory of Plasma Membrane Calcium Pump stimulation and activity

The ATP-driven Plasma Membrane Calcium pump or Ca(2+)-ATPase (PMCA) is characterized by a high affinity to calcium and a low transport rate compared to other transmembrane calcium transport proteins. It plays a crucial role for calcium extrusion from cells. Calmodulin is an intracellular calcium buffering protein which is capable in its Ca(2+) liganded form of stimulating the PMCA by increasing both the affinity to calcium and the maximum calcium transport rate. We introduce a new model of this stimulation process and derive analytical expressions for experimental observables in order to determine the model parameters on the basis of specific experiments. We furthermore develop a model for the pumping activity. The pumping description resolves the seeming contradiction of the Ca(2+):ATP stoichiometry of 1:1 during a translocation step and the observation that the pump binds two calcium ions at the intracellular site. The combination of the calcium pumping and the stimulation model correctly describes PMCA function. We find that the processes of calmodulin-calcium complex attachment to the pump and of stimulation have to be separated. Other PMCA properties are discussed in the framework of the model. The presented model can serve as a tool for calcium dynamics simulations and provides the possibility to characterize different pump isoforms by different type-specific parameter sets.Comment: 24 pages, 6 figure