1,433 research outputs found

    Electrophysiological evaluation of phrenic nerve injury during cardiac surgery – a prospective, controlled, clinical study

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    BACKGROUND: According to some reports, left hemidiaphragmatic paralysis due to phrenic nerve injury may occur following cardiac surgery. The purpose of this study was to document the effects on phrenic nerve injury of whole body hypothermia, use of ice-slush around the heart and mammary artery harvesting. METHODS: Electrophysiology of phrenic nerves was studied bilaterally in 78 subjects before and three weeks after cardiac or peripheral vascular surgery. In 49 patients, coronary artery bypass grafting (CABG) and heart valve replacement with moderate hypothermic (mean 28°C) cardiopulmonary bypass (CPB) were performed. In the other 29, CABG with beating heart was performed, or, in several cases, peripheral vascular surgery with normothermia. RESULTS: In all patients, measurements of bilateral phrenic nerve function were within normal limits before surgery. Three weeks after surgery, left phrenic nerve function was absent in five patients in the CPB and hypothermia group (3 in CABG and 2 in valve replacement). No phrenic nerve dysfunction was observed after surgery in the CABG with beating heart (no CPB) or the peripheral vascular groups. Except in the five patients with left phrenic nerve paralysis, mean phrenic nerve conduction latency time (ms) and amplitude (mV) did not differ statistically before and after surgery in either group (p > 0.05). CONCLUSIONS: Our results indicate that CPB with hypothermia and local ice-slush application around the heart play a role in phrenic nerve injury following cardiac surgery. Furthermore, phrenic nerve injury during cardiac surgery occurred in 10.2 % of our patients (CABG with CPB plus valve surgery)

    Maximal regularity for non-autonomous equations with measurable dependence on time

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    In this paper we study maximal LpL^p-regularity for evolution equations with time-dependent operators AA. We merely assume a measurable dependence on time. In the first part of the paper we present a new sufficient condition for the LpL^p-boundedness of a class of vector-valued singular integrals which does not rely on H\"ormander conditions in the time variable. This is then used to develop an abstract operator-theoretic approach to maximal regularity. The results are applied to the case of mm-th order elliptic operators AA with time and space-dependent coefficients. Here the highest order coefficients are assumed to be measurable in time and continuous in the space variables. This results in an Lp(Lq)L^p(L^q)-theory for such equations for p,q(1,)p,q\in (1, \infty). In the final section we extend a well-posedness result for quasilinear equations to the time-dependent setting. Here we give an example of a nonlinear parabolic PDE to which the result can be applied.Comment: Application to a quasilinear equation added. Accepted for publication in Potential Analysi

    Rapid interhemispheric climate links via the Australasian monsoon during the last deglaciation

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    Recent studies have proposed that millennial-scale reorganization of the ocean-atmosphere circulation drives increased upwelling in the Southern Ocean, leading to rising atmospheric carbon dioxide levels and ice age terminations. Southward migration of the global monsoon is thought to link the hemispheres during deglaciation, but vital evidence from the southern sector of the vast Australasian monsoon system is yet to emerge. Here we present a 230thorium-dated stalagmite oxygen isotope record of millennial-scale changes in Australian–Indonesian monsoon rainfall over the last 31,000 years. The record shows that abrupt southward shifts of the Australian–Indonesian monsoon were synchronous with North Atlantic cold intervals 17,600–11,500 years ago. The most prominent southward shift occurred in lock-step with Heinrich Stadial 1 (17,600–14,600 years ago), and rising atmospheric carbon dioxide. Our findings show that millennial-scale climate change was transmitted rapidly across Australasia and lend support to the idea that the 3,000-year-long Heinrich 1 interval could have been critical in driving the last deglaciation

    Metabolic, hygric and ventilatory physiology of a hypermetabolic marsupial, the honey possum (Tarsipes rostratus)

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    The honey possum is the only non-volant mammal to feed exclusively on a diet of nectar and pollen. Like other mammalian and avian nectarivores, previous studies indicated that the honey possum's basal metabolic rate was higher than predicted for a marsupial of equivalent body mass. However, these early measurements have been questioned. We re-examined the basal metabolic rate (2.52 +/- A 0.222 ml O(2) g(-1) h(-1)) of the honey possum and confirm that it is indeed higher (162%) than predicted for other marsupials both before and after accounting for phylogenetic history. This, together with its small body mass (5.4 +/- A 0.14 g; 1.3% of that predicted by phylogeny) may be attributed to its nectarivorous diet and mesic distribution. Its high-basal metabolic rate is associated with a high-standard body temperature (36.6 +/- A 0.48A degrees C) and oxygen extraction (19.4%), but interestingly the honey possum has a high point of relative water economy (17.0A degrees C) and its standard evaporative water loss (4.33 +/- A 0.394 mg H(2)O g(-1) h(-1)) is not elevated above that of other marsupials, despite its mesic habitat and high dietary water intake.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

    Age, period, and cohort analysis of regular dental care behavior and edentulism: A marginal approach

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    <p>Abstract</p> <p>Background</p> <p>To analyze the regular dental care behavior and prevalence of edentulism in adult Danes, reported in sequential cross-sectional oral health surveys by the application of a marginal approach to consider the possible clustering effect of birth cohorts.</p> <p>Methods</p> <p>Data from four sequential cross-sectional surveys of non-institutionalized Danes conducted from 1975-2005 comprising 4330 respondents aged 15+ years in 9 birth cohorts were analyzed. The key study variables were seeking dental care on an annual basis (ADC) and edentulism. For the analysis of ADC, survey year, age, gender, socio-economic status (SES) group, denture-wearing, and school dental care (SDC) during childhood were considered. For the analysis of edentulism, only respondents aged 35+ years were included. Survey year, age, gender, SES group, ADC, and SDC during childhood were considered as the independent factors. To take into account the clustering effect of birth cohorts, marginal logistic regressions with an independent correlation structure in generalized estimating equations (GEE) were carried out, with PROC GENMOD in SAS software.</p> <p>Results</p> <p>The overall proportion of people seeking ADC increased from 58.8% in 1975 to 86.7% in 2005, while for respondents aged 35 years or older, the overall prevalence of edentulism (35+ years) decreased from 36.4% in 1975 to 5.0% in 2005. Females, respondents in the higher SES group, in more recent survey years, with no denture, and receiving SDC in all grades during childhood were associated with higher probability of seeking ADC regularly (<it>P </it>< 0.05). The interaction of SDC and age (<it>P </it>< 0.0001) was significant. The probabilities of seeking ADC were even higher among subjects with SDC in all grades and aged 45 years or older. Females, older age group, respondents in earlier survey years, not seeking ADC, lower SES group, and not receiving SDC in all grades were associated with higher probability of being edentulous (<it>P </it>< 0.05).</p> <p>Conclusions</p> <p>With the use of GEE, the potential clustering effect of birth cohorts in sequential cross-sectional oral health survey data could be appropriately considered. The success of Danish dental health policy was demonstrated by a continued increase of regular dental visiting habits and tooth retention in adults because school dental care was provided to Danes in their childhood.</p

    Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

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    The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

    Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

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    The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

    Compressed representation of a partially defined integer function over multiple arguments

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    In OLAP (OnLine Analitical Processing) data are analysed in an n-dimensional cube. The cube may be represented as a partially defined function over n arguments. Considering that often the function is not defined everywhere, we ask: is there a known way of representing the function or the points in which it is defined, in a more compact manner than the trivial one
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