bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of overactive bladder on the brain: Central sequelae of a visceral pathology
Authors: Rickenbacher Elizabeth , Baez Madelyn A. , Hale Lyman , Leiser Steven C. , Zderic Stephen A. , Valentino Rita J.
Published: July 2008

Neural circuits that allow for reciprocal communication between the brain and viscera are critical for coordinating behavior with visceral activity. At the same time, these circuits are positioned to convey signals from pathologic events occurring in viscera to the brain, thereby providing a structural basis for comorbid central and peripheral symptoms. In the pons, Barrington's nucleus and the norepinephrine (NE) nucleus, locus coeruleus (LC), are integral to a circuit that links the pelvic viscera with the forebrain and coordinates pelvic visceral activity with arousal and behavior. Here, we demonstrate that a prevalent bladder dysfunction, produced by partial obstruction in rat, has an enduring disruptive impact on cortical activity through this circuit. Within 2 weeks of partial bladder obstruction, the activity of LC neurons was tonically elevated. LC hyperactivity was associated with cortical electroencephalographic activation that was characterized by decreased low-frequency (1–3 Hz) activity and prominent theta oscillations (6–8 Hz) that persisted for 4 weeks. Selective lesion of the LC–NE system significantly attenuated the cortical effects. The findings underscore the potential for significant neurobehavioral consequences of bladder disorders, including hyperarousal, sleep disturbances, and disruption of sensorimotor integration, as a result of central noradrenergic hyperactivity. The results further imply that pharmacological manipulation of central NE function may alleviate central sequelae of these visceral disorders.
TLR4-induced IFN-γ production increases TLR2 sensitivity and drives Gram-negative sepsis in mice
Authors: Spiller Stephan , Elson Greg , Ferstl Ruth , Dreher Stefan , Mueller Thomas , Freudenberg Marina , Daubeuf Bruno , Wagner Hermann , Kirschning Carsten J.
Published: July 2008

Gram-negative bacterial infection is a major cause of sepsis and septic shock. An important inducer of inflammation underlying both syndromes is the cellular recognition of bacterial products through pattern recognition receptors (PRRs), including Toll-like receptors (TLRs). We identified a novel antagonistic mAb (named 1A6) that recognizes the extracellular portion of the TLR4–MD-2 complex. If applied to mice before infection with clinical isolates of Salmonella enterica or Escherichia coli and subsequent antibiotic therapy, 1A6 prevented otherwise fatal shock, whereas application of 1A6 after infection was ineffective. In contrast, coapplication of 1A6 and an anti-TLR2 mAb up to 4 h after infection with Gram-negative bacteria, in combination with the start of antibiotic therapy (mimicking clinical conditions), provided robust protection. Consistent with our findings in mice, dual blockade of TLR2 and TLR4 inhibited TNF-α release from human peripheral blood mononuclear cells upon Gram-negative bacterial infection/antibiotic therapy. Both murine splenocytes and human PBMCs released IFN-γ in a TLR4-dependent manner, leading to enhanced surface TLR2 expression and sensitivity for TLR2 ligands. Our results implicate TLR2 as an important, TLR4-driven sensor of Gram-negative bacterial infection and provide a rationale for blockade of both TLRs, in addition to antibiotic therapy for the treatment of Gram-negative bacterial infection.
Measuring Acceptable Treatment Failure Rates for Community-Acquired Pneumonia: Potential for Reducing Duration of Treatment and Antimicrobial Resistance
Authors: Kaye Keith S. , Harris Anthony D. , McDonald Jay R. , Strausbaugh Larry J. , Perencevich Eli ,   Infectious Diseases Society of America Emerging Infections Network
Published: July 2008

Objective.

This study was designed to establish the rates of treatment failure for community-acquired pneumonia that are acceptable to knowledgeable and experienced physicians, in order to facilitate the interpretation of existing studies and the design of new studies aimed at optimizing the duration of antibiotic therapy. Reducing the duration of antibiotic therapy is one strategy for reducing antibiotic exposure and thereby minimizing the potential for the emergence of antimicrobial resistance.

Design.

Survey soliciting the acceptable failure rate for treatment given to an adult patient with uncomplicated community-acquired pneumonia treated with standard-of-care therapy in the outpatient setting. Analysis was performed using a modification of established methods of contingent valuation analysis.

Participants.

Six hundred eighty infectious diseases physicians in North America who were also members of the Emerging Infections Network of the Infectious Diseases Society of America.

Results.

Three hundred seventy-five (55.1%) of 680 physicians responded to the survey. The median acceptable failure rate for treatment was 13.5%. Five hundred ten respondents (75.0%) found a failure rate of 7.3% acceptable, and 170 respondents (25.0%) found a failure rate of 19.8% acceptable.

Conclusions.

This study identified the failure rates for treatment of community-acquired pneumonia that were acceptable to infectious disease physicians. This range of acceptable treatment failure rates may facilitate the design of studies aimed at optimizing the duration of antimicrobial therapy for community-acquired pneumonia.
Polynomial splittings of metabelian von Neumann rho–invariants of knots
Authors: Kim Se-Goo , Kim Taehee
Published: July 2008

We show that if the connected sum of two knots with coprime Alexander polynomials has vanishing von Neumann

ρ
\rho

–invariants associated with certain metabelian representations, then so do both knots. As an application, we give a new example of an infinite family of knots which are linearly independent in the knot concordance group.
Zero sets of smooth functions in the Pfaffian closure of an o-minimal structure
Authors: Jones G.
Published: July 2008

I show that in an o-minimal structure on the real field, satisfying certain conditions, every closed definable set is the zero set of a smooth definable function. The conditions are shown to hold in the Pfaffian closure of a polynomially bounded o-minimal structure having smooth cell decomposition.
Upper bound for isometric embeddings ℓ₂^{𝑚}→ℓ_{𝑝}ⁿ
Authors: Lyubich Yu.
Published: July 2008

The isometric embeddings

ℓ

2
;

K

m

→

ℓ

p
;

K

n

\ell _{2;\mathbb {K}}^m \rightarrow \ell _{p;\mathbb {K}}^n

(

m
≥
2

m\geq 2

,

p
∈
2

N

p\in 2\mathbb {N}

) over a field

K

∈
{

R

,

C

,

H

}

\mathbb {K}\in \lbrace \mathbb {R},\mathbb {C},\mathbb {H}\rbrace

are considered, and an upper bound for the minimal

n
n

is proved. In the commutative case (

K

≠

H

\mathbb {K}\neq \mathbb {H}

) the bound was obtained by Delbaen, Jarchow and Pełczyński (1998) in a different way.
A sufficient and necessary condition for the convergence of the sequence of successive approximations to a unique fixed point
Authors: Suzuki Tomonari
Published: July 2008

If

(
X
,
d
)

(X, d)

is a complete metric space and

T
:
X
→
X

T : X \to X

is a contraction mapping, then the conclusion of the Banach-Caccioppoli contraction principle is that the sequence of successive approximations of

T
T

starting from any point of the space converges to a unique fixed point. In this paper, we obtain a sufficient and necessary condition of the above conclusion in terms of the so-called strong Leader mappings.
Parametric representation and asymptotic starlikeness in ℂⁿ
Authors: Graham Ian , Hamada Hidetaka , Kohr Gabriela , Kohr Mirela
Published: July 2008

In this paper we consider the notion of asymptotic starlikeness in the Euclidean space

C

n

\mathbb {C}^n

. In the case of the maximum norm, asymptotic starlikeness was introduced by Poreda. We have modified his definition slightly, adding a boundedness condition. We prove that the notion of parametric representation which arises in Loewner theory can be characterized in terms of asymptotic starlikeness; i.e. they are equivalent notions. (A regularity assumption of Poreda is not needed.) In particular, starlike mappings and spirallike mappings of type

α
∈
(
−
π

/

2
,
π

/

2
)

\alpha \in (-\pi /2,\pi /2)

are asymptotically starlike. Therefore this notion is a natural generalization of starlikeness. However, we give an example of a spirallike mapping with respect to a linear operator which is not asymptotically starlike. In the case of one complex variable, any function in the class

S
S

is asymptotically starlike; however, in dimension

n
≥
2

n\geq 2

this is no longer true.
Stable algebras of entire functions
Authors: Coman Dan , Poletsky Evgeny
Published: July 2008

Suppose that

h
h

and

g
g

belong to the algebra

B

\mathcal {B}

generated by the rational functions and an entire function

f
f

of finite order on

C

n

\mathbb {C}^n

and that

h

/

g

h/g

has algebraic polar variety. We show that either

h

/

g
∈

B

h/g\in \mathcal {B}

or

f
=

q
1

e
p

+

q
2

f=q_1e^p+q_2

, where

p
p

is a polynomial and

q
1

,

q
2

q_1,q_2

are rational functions. In the latter case,

h

/

g

h/g

belongs to the algebra generated by the rational functions,

e
p

e^p

and

e

−
p

e^{-p}

.

The stability property is related to the problem of algebraic dependence of entire functions over the ring of polynomials. The case of algebraic dependence over

C

\mathbb {C}

of two entire or meromorphic functions on

C

n

\mathbb {C}^n

is completely resolved in this paper.
On the \overline{𝜇}–invariant of rational surface singularities
Authors: Stipsicz András
Published: July 2008

We show that for rational surface singularities with odd determinant the

μ
¯

\overline {\mu }

–invariant defined by W. Neumann is an obstruction for the link of the singularity to bound a rational homology 4–ball. We identify the

μ
¯

\overline {\mu }

–invariant with the corresponding correction term in Heegaard Floer theory.
The limiting distribution of the coefficients of the 𝑞-Catalan numbers
Authors: Chen William , Wang Carol , Wang Larry
Published: July 2008

We show that the limiting distributions of the coefficients of the

q
q

-Catalan numbers and the generalized

q
q

-Catalan numbers are normal. Despite the fact that these coefficients are not unimodal for small

n
n

, we conjecture that for sufficiently large

n
n

, the coefficients are unimodal and even log-concave except for a few terms of the head and tail.
Convergent martingales of operators and the Radon Nikodým property in Banach spaces
Authors: Cullender Stuart , Labuschagne Coenraad
Published: July 2008

We extend Troitsky’s ideas on measure-free martingales on Banach lattices to martingales of operators acting between a Banach lattice and a Banach space. We prove that each norm bounded martingale of cone absolutely summing (c.a.s.) operators (also known as

1
1

-concave operators), from a Banach lattice

E
E

to a Banach space

Y
Y

, can be generated by a single c.a.s.  operator. As a consequence, we obtain a characterization of Banach spaces with the Radon Nikodým property in terms of convergence of norm bounded martingales defined on the Chaney-Schaefer

l
l

-tensor product

E

⊗
~

l

Y

E\widetilde {\otimes }_l Y

. This extends a classical martingale characterization of the Radon Nikodým property, formulated in the Lebesgue-Bochner spaces

L
p

(
μ
,
Y
)

L^p(\mu ,Y)

(

1
>
p
>
∞

1> p >\infty

).
An 𝐸𝐿-labeling of the subgroup lattice
Authors: Woodroofe Russ
Published: July 2008

In a 2001 paper, Shareshian conjectured that the subgroup lattice of a finite, solvable group has an

E
L

EL

-labeling. We construct such a labeling and verify that our labeling has the expected properties.
Transduction of artificial transcriptional regulatory proteins into human cells
Authors: Yun Chae-Ok , Shin Hyun-Chul , Kim Tae-Dong , Yoon Wan-Hee , Kang Yoon-A , Kwon Heung-Sun , Kim Seong Keun , Kim Jin-Soo
Published: July 2008

Protein transduction (PT) is a method for delivering proteins into mammalian cells. PT is accomplished by linking a small peptide tag—called a PT domain (PTD)—to a protein of interest, which generates a functional fusion protein that can penetrate efficiently into mammalian cells. In order to study the functions of a transcription factor (TF) of interest, expression plasmids that encode the TF often are transfected into mammalian cells. However, the efficiency of DNA transfection is highly variable among different cell types and is usually very low in primary cells, stem cells and tumor cells. Zinc-finger transcription factors (ZF-TFs) can be tailor-made to target almost any gene in the human genome. However, the extremely low efficiency of DNA transfection into cancer cells, both in vivo and in vitro, limits the utility of ZF-TFs. Here, we report on an artificial ZF-TF that has been fused to a well-characterized PTD from the human immunodeficiency virus-1 (HIV-1) transcriptional activator protein, Tat. This ZF-TF targeted the endogenous promoter of the human VEGF-A gene. The PTD-attached ZF-TF was delivered efficiently into human cells in vitro. In addition, the VEGF-A-specific transcriptional repressor retarded the growth rate of tumor cells in a mouse xenograft experiment.
Non-invasive study of nerve fibres using laser interference microscopy
Authors: Brazhe A.R , Brazhe N.A , Rodionova N.N , Yusipovich A.I , Ignatyev P.S , Maksimov G.V , Mosekilde E , Sosnovtseva O.V
Published: July 2008

This paper presents the results of a laser interference microscopy study of the morphology and dynamical properties of myelinated nerve fibres. We describe the principles of operation of the phase-modulated laser interference microscope and show how this novel technique allows us to obtain information non-invasively about the internal structure of different regions of a nerve fibre. We also analyse the temporal variations in the internal optical properties in order to detect the rhythmic activity in the nerve fibre at different time scales and to shed light on the underlying biological processes. We observe pronounced frequencies in the dynamics of the optical properties and suggest that the oscillatory modes have similar origin in different regions, but different strengths and mutual modulation properties.
Marie Stopes: passionate about palaeobotany
Authors: Falcon‐Lang Howard
Published: July 2008

Marie Stopes (1880–1958) was one of the most flamboyant and influential figures of the early twentieth century. In addition to her well‐known work on birth control, she wrote a controversial sex manual for women, and produced numerous novels, plays and works of poetry. She is also remembered as a passionate advocate of eugenics, courting the architects of the Third Reich, and was identified, in some circles, as a threat to empire and country. But geology, and specifically palaeobotany, was her first love and indeed her life's most enduring passion. Although Stopes's life has been thoroughly dissected in four biographies, her geological career has been overshadowed by her later work. This is unfortunate, because she made major contributions to palaeobotany and coal research, and her scientific career, like her humanitarian endeavours, makes fascinating reading.
Urological surgery in patients aged 80 years and older: A 30‐year retrospective clinical study
Authors: Takao Tetsuya , Tsujimura Akira , Kiuchi Hiroshi , Komori Kazuhiko , Fujita Kazutoshi , Miyagawa Yasushi , Takada Shingo , Nonomura Norio , Okuyama Akihiko
Published: July 2008

Objectives:  To investigate changes in the management of cases over time, we undertook a retrospective analysis of urological surgeries carried out in patients aged 80 years and older in a single institution over the last 30 years.

Methods:  Between 1975 and 2004, 402 patients aged 80 years and older underwent 412 surgeries in our department. We reviewed the clinical records and analyzed changes in clinical data over time. We evaluated the observed comorbidities and postoperative complications in selected patients for whom complete clinical records were available. We then identified risk factors for postoperative complications by means of multiple logistic regression analysis.

Results:  The number of surgeries carried out in patients aged 80 years and older increased every 5 years. Over time, the number of endourological and laparoscopic surgeries increased. Of 255 patients, 225 (88.3%) had at least one comorbidity, and 51 patients had postoperative complications. The number of observed comorbidities, such as cardiovascular disorder, central nervous system disorder, and diabetes mellitus, increased over the most recent 10‐year period. However, there were no differences in postoperative complications over time. Male sex and open surgery were found to be independent risk factors for postoperative complications.

Conclusions:  Although elderly patients had various comorbidities, the postoperative morbidity rate was acceptable in our selected cases. This study may provide useful detailed information for patients 80 years and older who will undergo urological surgery.
IEEE 802.11s and the Philosophers’ problem
Authors: Denteneer Dee , Borst Sem , Ven Peter van de , Hiertz Guido
Published: July 2008

IEEE 802.11s is the task group in the IEEE that is in the process of standardizing wireless mesh networks. A hot topic in this standardization effort concerns the need for additional medium access functionality beyond the basic IEEE 802.11 carrier sense multiple access with collision avoidance (CSMA/CA). In this paper, we discuss the connection between CSMA/CA and Dijkstra's classical Philosophers’ problem, and its implications for the debate inside IEEE 802.11s. In an alternative view of this paper, we state some new mathematical models, theorems and conjectures related to the Philosophers’ problem.
An Extended Portmanteau Test for VARMA Models With Mixing Nonlinear Constraints
Authors: Arbués Ignacio
Published: July 2008

Abstract.  The portmanteau test is a widely used diagnostic tool for univariate and multivariate time‐series models. Its asymptotic distribution is known for the unconstrained vector autoregressive moving‐average (VARMA) case and for VAR models with constraints on the autoregressive coefficients. In this article, we give conditions under which the test can be applied to constrained VARMA models. Unfortunately, it cannot generally be applied to models with constraints that simultaneously affect the ARMA polynomial coefficients and the covariance matrix of the innovations (mixing constraints). This happens in latent‐variable models such as dynamic factor models (DFM). In addition, when there are constraints on the covariance matrix it seems convenient to check the goodness of fit using the zero‐lag residual covariances. We propose an extended portmanteau test that not only checks the autocorrelations of the residuals but also whether their covariance matrix is consistent with the constraints. We prove that the statistic is asymptotically distributed as a chi‐square for ARMA models under the assumption that the innovations have Gaussian‐like fourth‐order moments. We also show that the test is appropriate for the DFM, Peña–Box model and factor‐structural vector autoregression (FSVAR).
Local asymptotic normality and efficient estimation for INAR(p) models
Authors: Drost Feike C. , Van Den Akker Ramon , Werker Bas J. M.
Published: July 2008

Abstract.  Integer‐valued autoregressive (INAR) processes have been introduced to model non‐negative integer‐valued phenomena that evolve in time. The distribution of an INAR(p) process is determined by two parameters: a vector of survival probabilities and a probability distribution on the non‐negative integers, called an immigration distribution. This paper provides an efficient estimator of the parameters, and in particular, shows that the INAR(p) model has the Local Asymptotic Normality property.
THE BROCH CULTURES OF ATLANTIC SCOTLAND: ORIGINS, HIGH NOON AND DECLINE. PART 1: EARLY IRON AGE BEGINNINGS c.700–200 BC
Authors: MacKIE EUAN W.
Published: July 2008

Summary.  A new overview of the broch and wheelhouse‐building cultures is offered because recent comparable attempts have omitted substantial amounts of relevant data, such as discussion of the most plausible broch prototypes and of the details of the material cultural sequence, particularly the pottery. Well dated Early Iron Age roundhouse sites have often been described, but promontory forts of the same period, showing the specialized broch hollow wall, have not. The example at Clickhimin, Shetland, is now reliably dated to the sixth century BC at the latest and the associated pottery shows clear links with north‐west France. Another unexcavated example in Harris can be restored in some detail and shows how these sites were probably used. The pivotal role of Shetland in the emergence of the new culture is confirmed by the early dating of the broch at Old Scatness to the fourth/third centuries BC. However, a separate development of the round broch tower seems also to have occurred in the west, in the third/second centuries BC. English Early Iron Age pottery is also prominent in some of the earliest sites in the west and north. The picture is of a dynamic, maritime zone open to influences from several remote regions.
Impact of long‐term treatment with neurotoxic dideoxynucleoside antiretrovirals: implications for clinical care in resource‐limited settings
Authors: Hung CF , Gibson SA , Letendre SL , Lonergan JT , Marquie‐Beck JA , Vaida F , Ellis RJ
Published: July 2008

Objectives

A minority of HIV‐infected patients taking an antiretroviral (ARV) regimen containing dideoxynucleosides (d‐drugs) such as stavudine (d4T) and didanosine (DDI) experiences dose‐limiting neuropathic pain and paraesthesias, usually within weeks of starting these drugs. Because d‐drugs are among the few affordable options available in developing countries, continuing d‐drug therapy would be a desirable strategy for many HIV‐infected individuals. Therefore, we evaluated the safety of continuing d‐drug therapy.

Methods

In a US cohort, we compared the rates of worsening neuropathic symptoms and signs in HIV‐infected individuals on stable ARV regimens that did (n=252) or did not (n=250) include d‐drugs. Rates of worsening were compared using proportional hazards model and the log‐rank test.

Results

The risk ratios (RR) were not significantly larger for worsening neuropathy signs [0.94; 95% confidence interval (CI) 0.84–1.07] or symptoms (0.99; 95% CI 0.88–1.14) in patients taking d‐drugs continuously compared to those not taking d‐drugs.

Conclusions

Continued d‐drug exposure among patients tolerating an initial trial did not increase the risk of worsening neuropathy compared to non‐d‐drug‐containing regimens. If applicable in developing countries, these findings suggest that in most patients d‐drugs can be continued safely in the long term without increasing the risk of worsening neuropathy.
Mother‐to‐child transmission of HIV‐1: association with malaria prevention, anaemia and placental malaria*
Authors: Naniche D , Lahuerta M , Bardaji A , Sigauque B , Romagosa C , Berenguera A , Mandomando I , David C , Sanz S , Aponte J , Ordi J , Alonso P , Menendez C
Published: July 2008

Objectives

Malaria infection may impact on mother‐to‐child transmission (MTCT) of HIV‐1. Prevention of malaria in pregnancy could thus potentially affect MTCT of HIV. We studied the impact of intermittent preventive treatment during pregnancy (IPTp) on HIV‐1 MTCT in southern Mozambique.

Methods

A total of 207 HIV‐positive Mozambican pregnant women were enrolled in the study as part of a randomized placebo‐controlled trial of two‐dose sulfadoxine‐pyrimethamine (SP) IPTp in women receiving single‐dose nevirapine to prevent MTCT of HIV. HIV RNA viral load, maternal anaemia and peripheral and placental malaria were assessed at delivery. Infant HIV status was determined by DNA polymerase chain reaction (PCR) at 1 month of age.

Results

There were 19 transmissions of HIV in 153 mother–infant pairs. IPTp with SP did not have a significant impact on MTCT (11.8% in the SP group vs. 13.2% in the placebo group; P=0.784) or on maternal HIV RNA viral load [16 312 (interquartile range {IQR} 4076–69 296) HIV‐1 RNA copies/mL in the SP group vs. 18 274 (IQR 5471–74 104) copies/mL in the placebo group; P=0.715]. In multivariate analysis, maternal HIV RNA viral load [adjusted odds ratio (AOR) 19.9; 95% confidence interval (CI) 2.3–172; P=0.006] and anaemia (haematocrit <33%; AOR 7.5; 95% CI 1.7–32.4; P=0.007) were independent risk factors for MTCT. Placental malaria was associated with a decrease in MTCT (AOR 0.23; 95% CI 0.06–0.89; P=0.034).

Conclusions

IPTp with SP was not associated with a significant impact on MTCT of HIV. Maternal anaemia was an independent risk factor for MTCT.
Licked by the Mother Tongue: Imagining Everyday Sanskrit at Home and in the World
Authors: Hastings Adi
Published: July 2008

This paper examines the ways in which Sanskrit revivalists in contemporary India imagine social contexts for the production and reproduction of Sanskrit speech. In contrast to the received view of Sanskrit as being a ritual language par excellence, opposed at every step to the domestic sphere and everyday life, Sanskrit revivalists treat Sanskrit as a “mother tongue,” figuring the home as the primary site for the creation of an “everyday Sanskrit” world and the mother as the primary agent of this process of Sanskritizing the domestic sphere. “Domesticating Sanskrit,” the process of bringing the elevated ritual language down into everyday life, at the very same time “Sanskritizes the domestic,” that is, ritually transforms or elevates the home into a “Sanskrit home.” Moving outward from the Sanskritized domestic sphere, activists also imagine other contexts in which one could use Sanskrit, which nonetheless conforms to a notion of a Sanskrit interiority or domesticity. [India, Sanskrit, language revival, mother tongue, middle class, ritual]
Urban Princesses: Performance and “Women's Language” in Japan's Gothic/Lolita Subculture
Authors: Gagné Isaac
Published: July 2008

This paper investigates the linguistic strategies used in the counterpublic discourse of Gothic/Lolita, a young Japanese women's subculture of the late 1990s and early 2000s, and explores how the subculture and its practices are characterized by the Japanese media. Particular attention is paid to how subcultural magazines, websites, and Gothic/Lolitas themselves create and sustain a “virtual linguistic community” through a specialized lexicon of neologisms and re‐appropriated “women's language,” as well as negative identity practices that seek to define Gothic/Lolita against other subcultures and fashions such as kosupure [“Cosplay” i.e., Costume Play]. Additionally, an analysis of representations of Gothic/Lolita speech in two television programs reveals how the media constructs ambivalent images via iconization and erasure through narration and editing.[youth subculture, gender and language, speech community, counterpublic, Japan]
Schrödinger's Cat and the Ethnography of Law
Authors: Yngvesson Barbara , Coutin Susan
Published: July 2008

Drawing on research regarding undocumented immigration and transnational adoption, this essay argues that legal and ethnographic accounts retroactively instantiate potential realities that were there all along but are only made visible by official recognition. In this sense, the “field” that is at the center of ethnographic inquiry is brought into being by the activities of the ethnographer, just as the field of (un)documented bodies is brought into being by a judicial decree. At the same time, such authorizations of the real are haunted by the noise that is left behind. This noise makes itself known by its pull on official representations, pointing to the instability of our objects of study, the multidimensionality of everyday life, and the gaps and disjunctions that compel us to return to what was overlooked in order to make our ethnographies real.
Ethnography and Cognitive Psychology: Shared Dilemmas of the Local and Unlocatable
Authors: Richland Lindsey
Published: July 2008

Is there a productive intersection between ethnographic knowledge practices and the search for perduring structures of cognition within psychological inquiry? This article employs a brief ethnography of cognitive psychological experimentation to reveal that like ethnographers, experimental psychologists engage in a complex relationship between local particulars and generalized processes. In particular, I focus on the relationship between notions of “local” space and time and “unlocatable,” abstract cognitive processes to explore how psychological inquiry, like critical ethnography, is at once concerned with identifying abstract processes and intimately tied to the particulars of the research context.
A new proof of the non-tameness of the Nagata automorphism from the point of view of the Sarkisov program
Authors: Kishimoto Takashi
Published: July 2008

The Nagata automorphism is a kind of complicated automorphism on the affine 3-space ${\mathbb C}^3$. For a long time, it remained unknown whether or not the Nagata automorphism is tame until Shestakov and Umirbaev at last proved that it is not tame in 2004, by purely algebraic methods (e.g. Poisson algebra). In this paper, we consider a certain necessary condition for a given automorphism on ${\mathbb C}^3$ to be tame from the point of view of the Sarkisov program established by Corti. Furthermore, by using it, we shall give a new algebro-geometric proof of the non-tameness of the Nagata automorphism.
Varieties with quadratic entry locus, II
Authors: Ionescu Paltin , Russo Francesco
Published: July 2008

We continue the study, begun in [F. Russo, Varieties with quadratic entry locus. I, Preprint (2006), math. AG/0701889] , of secant defective manifolds having ‘simple entry loci’. We prove that such manifolds are rational and describe them in terms of tangential projections. Using also the work of [P. Ionescu and F. Russo, Conic-connected manifolds, Preprint (2006), math. AG/0701885], their classification is reduced to the case of Fano manifolds of high index, whose Picard group is generated by the hyperplane section class. Conjecturally, the former should be linear sections of rational homogeneous manifolds. We also provide evidence that the classification of linearly normal dual defective manifolds with Picard group generated by the hyperplane section should follow along the same lines.
Image Treatment of a 2D Vapor-Liquid Compound Droplet in a Linearized Steady Viscous Flow
Authors: Palaniappan D.
Published: July 2008

The classical method of images is used to construct closed form exact solutions for the two-dimensional (2D) perturbed flow fields in the presence of a 2D vapor-liquid compound droplet in the limit of low-Reynolds number. The geometry of the multiphase droplet is composed of two overlapping infinitely long cylinders Ca and Cb of radii a and b, respectively, intersecting at a vertex angle π∕2. The composite inclusion has the shape resembling a 2D snowman type of object with a vapor cylinder Ca partly protruded into the cylinder Cb filled with another fluid whose viscosity is different from that of the host fluid. The mathematical problem with this inclusion in the Stokes flow environment is formulated in terms of Stokes stream function with mixed boundary conditions at the boundary of the hybrid droplet. General expressions for the perturbed stream functions in the two phases are obtained in a straightforward fashion using Kelvin’s inversion together with shift and reflection properties of biharmonic functions. Application of our method to other related problems in creeping flow and possible further generalizations are also discussed. The general results are then exploited to derive singularity solutions for the hybrid droplet embedded in (i) a centered shear flow, (ii) a quadratic potential flow, and (iii) an extensional flow past the 2D vapor-liquid compound droplet. The image singularities in each case depend on the two radii of the cylinders, the center-to-center distance, and the viscosity ratio. The exact solutions are utilized to plot the flow streamlines and they show some interesting patterns. While the flow fields exterior to the droplet exhibit symmetrical topological structures, the interior flow fields show existence of free eddies—enclosed in a figure-eight separatrix—and stagnation points (hyperbolic points). The flow characteristics are influenced by the viscosity and radii ratios. Furthermore, the asymptotic analysis leads to a rather surprising conclusion that there is a (subdominant) uniform flow far away from the droplet in all cases. The existence of an origin, the natural center of the drop of the composite geometry, which neutralizes the uniform flow for a particular choice of the physical parameters, is illustrated. This reveals the sensitivity of the geometry in 2D Stokes flow. The present results may be of some interest in models involving a combination of stick and slip boundaries. Moreover, the method discussed here can be useful both as a teaching tool and as a building block for further calculations.
Understanding the Boundary Stencil Effects on the Adjacent Field Resolution in Compact Finite Differences
Authors: Jordan Stephen A.
Published: July 2008

When establishing the spatial resolution character of a composite compact finite differencing template for high-order field solutions, the stencils selected at nonperiodic boundaries are commonly treated independent of the interior scheme. This position quantifies a false influence of the boundary scheme on the resultant interior dispersive and dissipative consequences of the compound template. Of the three ingredients inherent in the composite template, only its numerical accuracy and global stability have been properly treated in a coupled fashion. Herein, we present a companion means for quantifying the resultant spatial resolution properties that lead to improved predictions of the salient problem physics. Compact boundary stencils with free parameters to minimize the field dispersion (or phase error) and dissipation are included in the procedure. Application of the coupled templates for resolving the viscous Burgers wave and two-dimensional acoustic scattering reveal significant differences in the predictive error.
Identification of Dynamic Parameter of a 3DOF Parallel Manipulator With Actuation Redundancy
Authors: Wu Jun , Wang Jinsong , Wang Liping
Published: July 2008

This paper deals with the dynamic parameter identification of a 3DOF parallel manipulator with actuation redundancy. A method for finding the parameter linear form of the dynamic equation is presented. Based on the virtual work principle, the dynamic equation for the application of dynamic parameter identification is obtained by extracting the dynamic parameters from inertial forces and moments of moving parts. Two-step identification approach is used to identify the dynamic parameters of the redundantly actuated parallel manipulator. The approach consists of two steps and utilizes simple point-to-point motions that lead to a separation of friction and rigid-body dynamics. The identified results are validated by experiments. Moreover, the experimental application of the identified model to a machine tool, which is created by combining the parallel manipulator with a 2DOF worktable, demonstrates the efficiency of dynamic parameter identification.
The Bending Fatigue Response of Fatigue Strength of PVC Pipe and Pipe Joints
Authors: Scavuzzo R. J. , Srivatsan T. S.
Published: July 2008

In a two-year program, seventy-eight specimens of PVC pipe with and without adhesive socket joints were tested in a four-point bending apparatus. Internal pressures were varied from atmospheric pressure (0 psig) to the rated internal pressure of 280 psig. Results of the plain pipe are compared to pipe with joints. All testing was done using a special apparatus developed to accommodate the large deformations required for fatigue testing of PVC pipes. This apparatus is described as well as the test results. Both strains and stresses are plotted against cycles-to-failure. Finite element elastic models of the socket joined specimens were analyzed to establish the areas of stress concentration and to explain the observed failure modes. Phase 1 testing indicated that the pipe internal pressure might have a significant effect on fatigue life. Joined pipe specimens with no internal pressure were weaker in bending fatigue than pressurized pipe. As a result, the internal pressure was systematically varied between 0 psig and the rated pressure 280 psig. Results of Phase 2 testing revealed a dependence on internal pressure. Also, the effects of an adhesive primer and roughening of the pipe surface on joint fatigue strength were also studied. Strain rate is known to exert a profound influence on the fatigue behavior of thermoplastic polymers. This effect has not been systematically studied and remains an unknown. This research was supported by two grants from the Pressure Vessel Research Council. Additional details of the research are compiled in the Welding Research Council (WRC) Bulletin 445.
Stress Analysis of Plastic Pipe Reinforced by Cross Helically Wound Steel Wires
Authors: Zheng Jinyang , Lin Xiufeng , Lu Yubin
Published: July 2008

Polyethylene pipe reinforced by cross helically wound steel wires (PSP), which has excellent performance, is a new type of plastic-matrix steel composite pipe. PSP consists of three continuous layers, i.e., inner PE layer, composite layer and outer PE layer. Elastic parameters of the composite layer were obtained with series and parallel models. Solutions for elastic stresses and strains of the PSP under internal pressure, external pressure, and axial force were developed by using the three-dimensional (3-D) anisotropic elasticity. Good agreement between theoretical results and experimental data shows that the presented model can well predict stresses and strains of the PSP.
Longitudinal Stress Due to Sustained Loads in a Nonlinear World
Authors: Diehl David W.
Published: July 2008

This paper reviews the current definition and common practices for evaluating longitudinal stresses due to sustained loads in piping systems and focuses on an ambiguity that may occur in these calculations where nonlinear boundary conditions (e.g. resting support liftoff) exist. Author then introduces and demonstrates a convenient and consistent method for calculating these stresses in the presence of these nonlinear boundary conditions.
Pressure Blow Out Assessment for Class 1 Piping With Local Wall Thinning
Authors: Hasegawa Kunio , Shibata Katsuyuki
Published: July 2008

Wall thinning caused by the flow of water in power piping systems became a major concern to the nuclear power industries. ASME Code Case N-597-3, “Requirements for Analytical Evaluation of Pipe Wall Thinning,” provides procedures and criteria for Code Class 2 and 3 piping for the evaluation of wall thinning. However, analytical evaluation procedure for Class 1 piping is not provideed in the Code Case. Recent full-scale experiments on locally thinned pipes have supported the development of more contemporary failure strength evaluation methodology for Class 1 piping. These evaluation methodologies are applicable for the loading type of bending, tensile or cyclic bending load. Prior to the failure by bending moment, tensile load or cyclic/seismic load, locally wall thinned pipes shall be considered pressure blow out by the internal pressure itself. This paper introduces the failure of a uniformly thinned cylinder by an internal pressure and describes limitation on wall thinning depth to avoid pressure blow out for Class 1 piping.
Autofrettaging Procedures on LDPE Hyper-Compressor Components
Authors: Giacomelli Enzo , Battagli Paolo , Campo Nicola , Graziani Franco
Published: July 2008

Hyper-compressors operating in plants with both vessel and tubular reactors are subject to very high pressures. Many cylinder components are exposed to pressures fluctuating between suction and discharge and therefore to high fatigue loads. To reach high endurance capabilities, the cylinder components have to be pre-compressed in order to keep them operating under compressive stress whenever possible. Special materials and shrink fitting procedures are usually required. In other cases or for complex shapes, other technological processes, like autofrettage, are also applied to further improve the pre-stress level. The application of autofrettage requires special rigs to withstand the severe processing conditions and an intensifier to reach final pressures up to 1.4 GPa. Suitable sealing elements, identified through extensive experience, allow to reach very high pressures required to adequately strain the material. The pressure transmitting fluid must also have specific characteristics to avoid solidification. The autofrettage process requires special conditions to increase, maintain and remove the pressure on the system in order to achieve the desired deformation when the plastic strain region is reached. This produces an optimum autofrettage result for enhanced reliability and safe operation of the components.
Thermohydraulic Bahaviour Flow in a Model Representing a Simplified Geometry of a Feed Water Nozzle of a Submarine Nuclear Steam Generator
Authors: Boissiere Xavier , Laine Christian
Published: July 2008

The feed water nozzle of the steam generator constitutes an area where exists a very high spatial thermal gradient, and also occasionally a temporal thermal gradient, for example during starting of the installation. In order to protect the vessel from thermal fatigue, the cold pipe is surrounded at the connection by an annular water layer to ensure thermal uncoupling. However the flow behavior remains unknown. In a first step, we improve our knowledge concerning the hydraulic behavior thanks to a model representing a simplified geometry of the nozzle environment. In a second step we confirm this behavior thanks to CFD parametric analysis of the geometry. These two first steps allowed us to identify the best geometrical dimensions, such as the depth and the thickness of the annular cavity, but also the curved or sharp junction. These parameters concern the mass transfer in the annular cavity. The current step concerns the thermal effects. The analysis is performed by both experimental and numerical approach. The experimental method to identify heat fluxes is presented, then the results are discussed and compared to numerical results.
Nonlinear Dynamic Analysis of Reactor Coolant Loop Coupled With Reactor Building
Authors: Suanno Rodolfo L. M. , Prates Carlos L. M. , Prates de Lima Maria Ineˆs L. , Cardoso Tarci´sio F.
Published: July 2008

The steam generator (SG) snubber elimination process in a nuclear power plant requires a new evaluation of the structural behavior of the complete primary system components for licensing purposes. The forces and stresses have to be evaluated in all supports, piping, nozzles and internals of all components of the reactor coolant loop (RCL) for the required load cases, including dead weight, thermal conditions, seismic excitations and postulated piping ruptures. The SG snubber elimination intends to obtain a safer operating condition, avoiding problems with snubber maintenance, inspection and mal-function. The paper describes the methodology adopted for this type of analysis, where a very detailed modeling procedure is required, both for the primary loop itself, where nonlinearities are introduced to represent the supporting devices, as well as for the coupling with the reactor building structure. The piping and the components (Reactor vessel, SG and pumps) are modeled in order to represent their weight distribution, stiffness and supporting conditions in detail. The reactor building complete 3D-finite element model is reduced to a corresponding representative simple beam model in order to make the nonlinear dynamic analysis feasible. The seismic response spectra from both building models were compared at supporting points of the primary circuit in order to guarantee that the simple beam model represents the behavior of the refined building model in a correct way. The dynamic analysis is performed with seismic acceleration time histories applied at the foundation of the reactor building model and a direct integration method is used. The Rayleigh damping values as well as the effects in the results of refining the integration time steps are discussed. The impact forces due to postulated pipe ruptures are also evaluated as impact loads. The results of these analyses are displacements, accelerations and forces in all structural elements and their supports, as well as time histories and response spectra for the stress analysis of the component internal structures.
Modelling the Kinetics of Hydrogen Evolution on Metals for Nuclear Applications
Authors: Trethewey Kenneth R.
Published: July 2008

It is well known that some metals suffer damage caused by the evolution of hydrogen in certain conditions in nuclear applications. Of particular current interest is the use of alloys for use in containers for the long-term storage of high level nuclear waste. Calculations for the rates of corrosion of metals where hydrogen evolution is possible rely upon measurements of the reaction kinetics, but it is difficult to obtain reliable and accurate values for the kinetic constants. Standard electrochemical tests can be used, but the analysis of the results is complex because of the need to deconvolute the curves. This paper presents a computer model for the analysis of the data that is checked by its use on experimental data from a number of nuclear materials.
Can Coverage of Alloy 800H in ASME Section III Subsection NH be Extended to 850°C?
Authors: Swindeman Robert W. , Swindeman Michael J. , Ren Weiju
Published: July 2008

Several solid-solution austenitic alloys are under consideration for the construction of components for high-temperature gas-cooled reactors of interest to the Generation IV nuclear reactor projects. However, coverage for these alloys in ASME Section III, Subsection NH is inadequate. Alloy 800H, for example, is included to 760°C whereas there is a need for coverage to 850°C. Efforts have begun to identify the existing database for Alloy 800H and, after evaluation, further identify the experimental and analytical research needed to extend coverage to 850°C. This paper summarizes progress in the first year of the effort. Emphasis is on the examination of the tensile, creep-rupture and fatigue database that exists worldwide. Also, the procedures used to set the allowable stress intensities and strain limits are being re-examined. Damage models to include environmental effects are included in the evaluation.
Towards a Unified Solution Method for Fluid-Structure Interaction Problems: Progress and Challenges
Authors: Papadakis G. , Giannopapa C. G.
Published: July 2008

The paper presents the progress in the development of a novel unified method for solving coupled fluid-structure interaction problems as well as the associated major challenges. The new approach is based on the fact that there are four fundamental equations in continuum mechanics: the continuity equation and the three momentum equations that describe Newton’s second law in three directions. These equations are valid for fluids and solids, the difference being in the constitutive relations that provide the internal stresses in the momentum equations: in solids the stress tensor is a function of the strain tensor while in fluids the viscous stress tensor depends on the rate of strain tensor. The equations are written in such a way that both media have the same unknown variables, namely the three velocity components and pressure. The same discretisation technique (finite volume) and solution method (segregated approach) are used irrespective of the medium. Also the same methodology to handle the pressure-velocity coupling is employed. A common set of variables as well as a unified discretisation and solution method leads to a strong coupling between the two media and is very beneficial for the robustness of the algorithm. Significant challenges include the derivation of consistent boundary conditions for the pressure equation in boundaries with prescribed traction as well as the handling of discontinuity of pressure at the fluid-structure interface.