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Search Results: 1 - 10 of 10090 matches for " Kochanek Patrick "
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Cardiac arrest in children
Tress Erika,Kochanek Patrick,Saladino Richard,Manole Mioara
Journal of Emergencies, Trauma and Shock , 2010,
Abstract: Major advances in the field of pediatric cardiac arrest (CA) were made during the last decade, starting with the publication of pediatric Utstein guidelines, the 2005 recommendations by the International Liaison Committee on Resuscitation, and culminating in multicenter collaborations. The epidemiology and pathophysiology of in-hospital and out-of-hospital CA are now well described. Four phases of CA are described and the term "post-cardiac arrest syndrome" has been proposed, along with treatment goals for each of its four phases: immediate post-arrest, early post-arrest, intermediate and recovery phase. Hypothermia is recommended to be considered as a therapy for post-CA syndrome in comatose patients after CA, and large multicenter prospective studies are underway. We reviewed landmark articles related to pediatric CA published during the last decade. We present the current knowledge of epidemiology, pathophysiology and treatment of CA relevant to pre-hospital and acute care health practitioners.
Bench-to-bedside review: Apoptosis/programmed cell death triggered by traumatic brain injury
Xiaopeng Zhang, Yaming Chen, Larry W Jenkins, Patrick M Kochanek, Robert SB Clark
Critical Care , 2004, DOI: 10.1186/cc2950
Abstract: Each year in the USA, more than 1 million patients undergo medical evaluation and treatment for acute head injury [1]. In the USA there were an average of 53,288 annual traumatic brain injury (TBI)-related deaths from 1989 to 1998, or 19.3 per 10,000 [2]. In Germany, the TBI death rate in 1996 was 11.5 per 10,000, with a total of 9415 deaths [3]. A 15-year study in Denmark showed that the mortality of children after TBI was 22%, and among those survivors of severe head injury, significant numbers were found to have serious neurological disabilities [4]. A regional population-based study in France showed that the mortality of hospitalized TBI patients was as high as 30.0% [5]. Similar data can be found in studies from a variety of demographic and cultural settings [6,7]. Acute and long-term care of TBI patients has become a significant social and economic burden around the world [8-10].The neurological outcome of TBI victims depends on the extent of the primary brain insult caused by trauma itself, and on the secondary neurochemical and pathophysiological changes occurring as a consequence of the mechanical injury, which leads to additional neuronal cell loss. Although a long list of experimental studies suggest that reduction or prevention of secondary brain injury after TBI is possible, clinical trials have failed to show benefit from therapeutic strategies proven to be effective in the laboratory [11-13]. This might reflect the diverse nature of clinical TBI and/or perhaps an incomplete understanding of the mechanisms of secondary neuronal loss.Two waves of neuronal cell death occur after TBI. Immediately after mechanical trauma due to impact or penetration, neurons can die by necrosis caused by membrane disruption, irreversible metabolic disturbances and/or excitotoxicity [14]. Early application of neuroprotective protocols seems critical for any possibility of reducing neuronal necrosis; however, this is beyond the scope of the current review. The second wave of
The Potential for Bio-Mediators and Biomarkers in Pediatric Traumatic Brain Injury and Neurocritical Care
Patrick M. Kochanek,Rachel P. Berger,Alicia K. Au,Robert S. B. Clark
Frontiers in Neurology , 2013, DOI: 10.3389/fneur.2013.00040
Abstract: The use of biomarkers of brain injury in pediatric neurocritical care has been explored for at least 15 years. Two general lines of research on biomarkers in pediatric brain injury have been pursued: (1) studies of “bio-mediators” in cerebrospinal fluid (CSF) of children after traumatic brain injury (TBI) to explore the components of the secondary injury cascades in an attempt to identify potential therapeutic targets and (2) studies of the release of structural proteins into the CSF, serum, or urine in order to diagnose, monitor, and/or prognosticate in patients with TBI or other pediatric neurocritical care conditions. Unique age-related differences in brain biology, disease processes, and clinical applications mandate the development and testing of brain injury bio-mediators and biomarkers specifically in pediatric neurocritical care applications. Finally, although much of the early work on biomarkers of brain injury in pediatrics has focused on TBI, new applications are emerging across a wide range of conditions specifically for pediatric neurocritical care including abusive head trauma, cardiopulmonary arrest, septic shock, extracorporeal membrane oxygenation, hydrocephalus, and cardiac surgery. The potential scope of the utility of biomarkers in pediatric neurocritical care is thus also discussed.
Eight New Quasar Lenses from the Sloan Digital Sky Survey Quasar Lens Search
Issha Kayo,Naohisa Inada,Masamune Oguri,Tomoki Morokuma,Patrick B. Hall,Christopher S. Kochanek,Donald P. Schneider
Physics , 2009, DOI: 10.1088/0004-6256/139/4/1614
Abstract: We report the discovery and confirmation of eight new two-image lensed quasars by the Sloan Digital Sky Survey (SDSS) Quasar Lens Search. The lenses are SDSSJ0904+1512 (image separation \theta=1"13, source redshift z_s=1.826), SDSSJ1054+2733 (\theta=1"27, z_s=1.452), SDSSJ1055+4628 (\theta=1"15, z_s=1.249), SDSSJ1131+1915 (\theta=1"46, z_s=2.915), SDSSJ1304+2001 (\theta=1"87, z_s=2.175), SDSSJ1349+1227 (\theta=3"00, z_s=1.722), SDSSJ1455+1447 (\theta=1"73, z_s=1.424), and SDSSJ1620+1203 (\theta=2"77, z_s=1.158). Three of them, SDSSJ1055+4628, SDSSJ1455+1447, and SDSSJ1620+1203, satisfy the criteria for constructing our statistical sample for studying the cosmological model. Based on galactic absorption lines of the lens galaxies, we also derive lens redshifts of z_l=0.398 and z_l=0.513 for SDSSJ1620+1203 and the previously discovered lens SDSSJ0746+4403, respectively.
Stability of vector measures and twisted sums of Banach spaces
Tomasz Kochanek
Mathematics , 2012,
Abstract: A Banach space $X$ is said to have the $\mathsf{SVM}$ (stability of vector measures) property if there exists a constant $v<\infty$ such that for any algebra of sets $\mathcal F$, and any function $\nu\colon\mathcal F\to X$ satisfying $$\|\nu(A\cup B)-\nu(A)-\nu(B)\|\leq 1\quad{for disjoint}A,B\in\mathcal F,$$there is a vector measure $\mu\colon\mathcal F\to X$ with $\|\nu(A)-\mu(A)\|\leq v$ for all $A\in\mathcal F$. If this condition is valid when restricted to set algebras $\mathcal F$ of cardinality less than some fixed cardinal number $\kappa$, then we say that $X$ has the $\kappa$-$\mathsf{SVM}$ property. The least cardinal $\kappa$ for which $X$ does not have the $\kappa$-$\mathsf{SVM}$ property (if it exists) is called the $\mathsf{SVM}$ character of $X$. We apply the machinery of twisted sums and quasi-linear maps to characterise these properties and to determine $\mathsf{SVM}$ characters for many classical Banach spaces. We also discuss connections between the $\kappa$-$\mathsf{SVM}$ property, $\kappa$-injectivity and the `three-space' problem.
$\mathcal F$-bases with brackets and with individual brackets in Banach spaces
Tomasz Kochanek
Mathematics , 2012,
Abstract: We provide a partial answer to the question of Vladimir Kadets whether given an $\mathcal F$-basis of a Banach space $X$, with respect to some filter $\mathcal F\subset \mathcal P(\mathbb N)$, the coordinate functionals are continuous. The answer is positive if the character of $\mathcal F$ is less than $\mathfrak{p}$. In this case every $\mathcal F$-basis with individual brackets is an $M$-basis with brackets determined by a set from $\mathcal F$.
On Return Periodof the Largest Historical Flood  [PDF]
Witold G. Strupczewski, Krzysztof Kochanek, Ewa Bogdanowicz
Journal of Geoscience and Environment Protection (GEP) , 2014, DOI: 10.4236/gep.2014.23019
Abstract:

The use of nonsystematic flood data for statistical purposes depends on reliability of assessment both flood magnitudes and their return period. The earliest known extreme flood year is usually the beginning of the historical record. Even though the magnitudes of historic floods are properly assessed, a problem of their retun periods remains unsolved. Only largest flood (XM) is known during whole historical period and its occurrence carves the mark of the beginning of the historical period and defines its length (L). So, it is a common practice of using the earliest known flood year as the beginning of the record. It means that the L value selected is an empirical estimate of the lower bound on the effective historical length M. The estimation of the return period of XM based on its occurrence, i.e. , gives the severe upward bias. Problem is to estimate the time period (M) representative of the largest observed flood XM. From the discrete uniform distribution with support of the probability of the L position of XM one gets

Almost orthogonally additive functions
Tomasz Kochanek,Wirginia Wyrobek-Kochanek
Mathematics , 2012,
Abstract: If a function $f$, acting on a Euclidean space $\mathbb{R}^n$, is "almost" orthogonally additive in the sense that $f(x+y)=f(x)+f(y)$ for all $(x,y)\in\bot\setminus Z$, where $Z$ is a "negligible" subset of the $(2n-1)$-dimensional manifold $\bot\subset\mathbb{R}^{2n}$, then $f$ coincides almost everywhere with some orthogonally additive mapping.
Gravitational Lensing Limits on Cold Dark Matter and Its Variants
Christopher S. Kochanek
Physics , 1994, DOI: 10.1086/176417
Abstract: Standard $\Omega_0=1$ cold dark matter (CDM) needs $0.27 < \sigma_8 < 0.63$ ($2\sigma$) to fit the observed number of large separation lenses, and the constraint is nearly independent of $H_0=100h^{-1}\kms$ Mpc$^{-1}$. This range is strongly inconsistent with the COBE estimate of $\sigma_8=(2.8\pm0.2)h$. Tilting the primordial spectrum $\propto k^n$ from $n=1$ to $0.3 \ltorder n \ltorder 0.7$, using an effective Hubble constant of $0.15 \ltorder \Gamma=h \ltorder 0.30$, or reducing the matter density to $0.15 \ltorder \Omega_0 h \ltorder 0.3$ either with no cosmological constant ($\lambda_0=0$) or in a flat universe with a cosmological constant ($\Omega_0+\lambda_0=1$) can bring the lensing estimate of $\sigma_8$ into agreement with the COBE estimates. The models and values for $\sigma_8$ consistent with both lensing and COBE match the estimates from the local number density of clusters and correlation functions. The conclusions are insensitive to systematic errors except for the assumption that cluster core radii are singular. If clusters with $\rho\propto(r^2+s^2)^{-1}$ have core radii exceeding $s = 15h^{-1}\sigma_3^2$ kpc for a cluster with velocity dispersion $\sigma=10^3\sigma_3 \kms$ then the estimates are invalid. There is, however, a fine tuning problem in making the cluster core radii large enough to invalidate the estimates of $\sigma_8$ while producing several lenses that do not have central or ``odd images.'' The estimated completeness of the current samples of lenses larger than $5\parcs0$ is 20\%, because neither quasar surveys nor lens surveys are optimized to this class of lenses.
The Mass of the Milky Way Galaxy
Christopher S. Kochanek
Physics , 1995, DOI: 10.1086/176724
Abstract: We use the Jaffe model as a global mass distribution for the Galaxy and determine the circular velocity $v_c$ and the Jaffe radius $r_j$ using the satellites of the Galaxy, estimates of the local escape velocity of stars, the constraints imposed by the known rotation curve of the disk, and the Local Group timing model. The models include the systematic uncertainties in the isotropy of the satellite orbits, the form of the stellar distribution function near the escape velocity, and the ellipticity of the M31/Galaxy orbit. If we include the Local Group timing constraint, then Leo I is bound, $v_c=230\pm30\kms$, and $r_j=180$ kpc (110 kpc $\ltorder r_j \ltorder $ 300 kpc) at 90\% confidence. The satellite orbits are nearly isotropic with $\beta=1-\sigma_\theta^2/\sigma_r^2=0.07$ ($-0.7 \ltorder \beta \ltorder 0.6$) and the stellar distribution function near the escape velocity is $f(\epsilon)\propto \epsilon^k$ with $k_r=3.7$ ($0.8 \ltorder k_r \ltorder 7.6$) where $k_r=k+5/2$. While not an accurate measurement of $k$, it is consistent with models of violent relaxation ($k=3/2$). The mass inside 50 kpc is $(5.4\pm1.3)\times 10^{11} M_\odot$. Higher mass models require that M31 is on its second orbit and that the halo is larger than the classical tidal limit of the binary. Such models must have a significant fraction of the Local Group mass in an extended Local Group halo. Lower mass models require that both M31 and Leo I are unbound, but there is no plausible mechanism to produce the observed deviations of M31 and Leo I from their expected velocities in an unbound system. If we do not use the Local Group timing model, the median mass of the Galaxy {\it increases} significantly, and the error bars broaden. Using only the satellite, escape velocity, and disk rotation curve constraints, the
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