bluuebunny/crossref_metadata_2025_split huggingface dataset:
Existence and nonexistence of global positive solutions to nonlinear diffusion problems with nonlinear absorption through the boundary
Authors: Wang Mingxin , Wu Yonghui 
Published: July 2002

This paper deals with the existence and nonexistence of global positive solutions to

u
t

=
Δ
ln
⁡
(
1
+
u
)

u_t=\Delta \ln (1+u)

in

Ω
×
(
0
,
+
∞
)

\Omega \times (0, +\infty )

,
\[

∂
ln
⁡
(
1
+
u
)

∂
n

=

1
+
u

(
ln
⁡
(
1
+
u
)

)

α

on
∂
Ω
×
(
0
,
+
∞
)
,

\frac {\partial \ln (1+u)}{\partial n}=\sqrt {1+u}(\ln (1+u))^{\alpha } \quad \text {on} \partial \Omega \times (0, +\infty ),

\]
and

u
(
x
,
0
)
=

u
0

(
x
)

u(x, 0)=u_0(x)

in

Ω
\Omega

. Here

α
≥
0

\alpha \geq 0

is a parameter,

Ω
⊂

R

N

\Omega \subset \mathbb {R}^N

is a bounded smooth domain. After pointing out the mistakes in Global behavior of positive solutions to nonlinear diffusion problems with nonlinear absorption through the boundary, SIAM J. Math. Anal. 24 (1993), 317–326, by N. Wolanski, which claims that, for

Ω
=

B
R

\Omega =B_R

the ball of

R

N

\mathbb {R}^N

, the positive solution exists globally if and only if

α
≤
1

\alpha \leq 1

, we reconsider the same problem in general bounded domain

Ω
\Omega

and obtain that every positive solution exists globally if and only if

α
≤

1

/

2

\alpha \leq {1/2}

.
Unramified cohomology and Witt groups of anisotropic Pfister quadrics
Authors: Sujatha R. 
Published: July 2002

The unramified Witt group of an anisotropic conic over a field

k
k

, with

c
h
a
r

k
≠
2

char~k \neq 2

, defined by the form

⟨
1
,
−
a
,
−
b
⟩

\langle 1,-a,-b\rangle

is known to be a quotient of the Witt group

W
(
k
)

W(k)

of

k
k

and isomorphic to

W
(

k

)

/

⟨
1
,
−
a
,
−
b
,
a
b
⟩
W
(

k

)

W( {k})/\langle 1,-a,-b,ab \rangle W( {k})

. We compute the unramified cohomology group

H

n
r

3

k
(

C

)

H^{3}_{nr}{k({C})}

, where

C
C

is the three dimensional anisotropic quadric defined by the quadratic form

⟨
1
,
−
a
,
−
b
,
a
b
,
−
c
⟩

\langle 1,-a,-b,ab,-c\rangle

over

k
k

. We use these computations to study the unramified Witt group of

C
C

.
A condition on the value function both necessary and sufficient for full regularity of minimizers of one-dimensional variational problems
Authors: Sychev M. , Mizel V. 
Published: July 2002

We study two-point Lagrange problems for integrands

L
=
L
(
t
,
u
,
v
)

L= L(t,u,v)

:

F
[
u
]
=

∫
a
b

L
(
t
,
u
(
t
)
,

u
˙

(
t
)
)

a
m
p
;

d
t
→
inf
,

a
m
p
;
u
∈

A

=
{
v
∈

W

1
,
1

(
[
a
,
b
]
;

R

n

)

|

v
(
a
)
=
A
,
v
(
b
)
=
B
}
.

\begin{equation}\tag {P} \begin {split} F[u]=\int _a^b L(t,u(t),\dot u(t))&\,dt \to \inf ,\\ & u\in \mathcal A=\{v\in W^{1,1} ([a,b];\mathbb R^n)|v(a)=A,v(b)=B\}. \end{split} \end{equation}

Under very weak regularity hypotheses [

L
L

is Hölder continuous and locally elliptic on each compact subset of

R

×

R

n

×

R

n

\mathbb R\times \mathbb R^n\times \mathbb R^n

] we obtain, when

L
L

is of superlinear growth in

v
v

, a characterization of problems in which the minimizers of (P) are

C
1

C^1

-regular for all boundary data. This characterization involves the behavior of the value function

S
S

:

R

×

R

n

×

R

×

R

n

→

R

\mathbb R\times \mathbb R^n\times \mathbb R\times \mathbb R^n\to \mathbb R

defined by

S
(
a
,
A
,
b
,
B
)
=

inf

A

F

S(a,A,b,B)=\inf _{\mathcal A} F

. Namely, all minimizers for (P) are

C
1

C^1

-regular in neighborhoods of

a
a

and

b
b

if and only if

S
S

is Lipschitz continuous at

(
a
,
A
,
b
,
B
)

(a,A,b,B)

. Consequently problems (P) possessing no singular minimizers are characterized in cases where not even a weak form of the Euler-Lagrange equations is available for guidance. Full regularity results for problems where

L
L

is nearly autonomous, nearly independent of

u
u

, or jointly convex in

(
u
,
v
)

(u,v)

are presented.
A theorem on zeta functions associated with polynomials
Authors: Eie Minking , Chen Kwang-Wu 
Published: July 2002

Let

β
=
(

β

1

,
…
,

β

r

)

\beta =(\beta _{1},\ldots ,\beta _{r})

be an

r
r

-tuple of non-negative integers and

P

j

(
X
)

P_{j}(X)

(
j
=
1
,
2
,
…
,
n
)

(j=1,2,\ldots ,n)

be polynomials in

R

[

X

1

,
…
,

X

r

]

{\mathbb {R}}[X_{1},\ldots ,X_{r}]

such that

P

j

(
n
)
>
0

P_{j}(n)>0

for all

n
∈

N

r

n\in {\mathbb {N}}^{r}

and the series

∑

n
∈

N

r

P

j

(
n

)

−
s

\begin{equation*}\sum _{n\in {\mathbb {N}}^{r}} P_{j}(n)^{-s}\end{equation*}

is absolutely convergent for Re

s
>

σ

j

>
0

s>\sigma _{j}>0

. We consider the zeta functions

Z
(

P

j

,
β
,
s
)
=

∑

n
∈

N

r

n

β

P

j

(
n

)

−
s

,

Re
s
>

|

β

|

+

σ

j

,

1
≤
j
≤
n
.

\begin{equation*}Z(P_{j},\beta ,s)=\sum _{n\in {\mathbb {N}}^{r}}n^{\beta } P_{j}(n)^{-s},\quad \text {Re} s>|\beta |+\sigma _{j}, \quad 1\leq j\leq n.\end{equation*}

All these zeta functions

Z
(

∏

j
=
1

n

P

j

,
β
,
s
)

Z(\prod ^{n}_{j=1} P_{j},\beta ,s)

and

Z
(

P

j

,
β
,
s
)

(
j
=
1
,
2
,
…
,
n
)

Z(P_{j},\beta ,s)\quad (j=1,2,\ldots ,n)

are analytic functions of

s
s

when Re

s

\, s

is sufficiently large and they have meromorphic analytic continuations in the whole complex plane. In this paper we shall prove that

Z
(

∏

j
=
1

n

P

j

,
β
,
0
)
=

1
n

∑

j
=
1

n

Z
(

P

j

,
β
,
0
)
.

\begin{equation*}Z(\prod _{j=1}^{n} P_{j},\beta ,0)=\frac {1}{n} \sum _{j=1}^{n} Z(P_{j},\beta ,0).\end{equation*}

As an immediate application, we use it to evaluate the special values of zeta functions associated with products of linear forms as considered by Shintani and the first author.
Maximal function estimates of solutions to general dispersive partial differential equations
Authors: Heinig Hans , Wang Sichun 
Published: July 2002

Let

u
(
x
,
t
)
=
(

S
Ω

f
)
(
x
,
t
)

u(x,t)=(S_\Omega f)(x,t)

be the solution of the general dispersive initial value problem:
\[

∂
t

u
−
i
Ω
(
D
)
u
=
0
,

u
(
x
,
0
)
=
f
(
x
)
,

(
x
,
t
)
∈

R

n

×

R

\partial _tu-i\Omega (D)u=0, \quad u(x,0)=f(x), \qquad (x,t)\in \mathbb {R}^n \times \mathbb {R}

\]
and

S
Ω

∗
∗

f

S^{**}_\Omega f

the global maximal operator of

S
Ω

f

S_\Omega f

. Sharp weighted

L
p

L^p

-esimates for

S
Ω

∗
∗

f

S^{**}_\Omega f

with

f
∈

H
s

(

R

n

)

f\in H_s(\mathbb {R}^n)

are given for general phase functions

Ω
\Omega

.
𝐿^{𝑝} estimates for nonvariational hypoelliptic operators with 𝑉𝑀𝑂 coefficients
Authors: Bramanti Marco , Brandolini Luca 
Published: July 2002

Let

X
1

,

X
2

,
…
,

X
q

X_1,X_2,\ldots ,X_q

be a system of real smooth vector fields, satisfying Hörmander’s condition in some bounded domain

Ω
⊂

R

n

\Omega \subset \mathbb {R}^n

(

n
>
q

n>q

). We consider the differential operator

L

=

∑

i
=
1

q

a

i
j

(
x
)

X
i

X
j

,

\begin{equation*} \mathcal {L}=\sum _{i=1}^qa_{ij}(x)X_iX_j, \end{equation*}

where the coefficients

a

i
j

(
x
)

a_{ij}(x)

are real valued, bounded measurable functions, satisfying the uniform ellipticity condition:

μ

|

ξ

|

2

≤

∑

i
,
j
=
1

q

a

i
j

(
x
)

ξ
i

ξ
j

≤

μ

−
1

|

ξ

|

2

\begin{equation*} \mu |\xi |^2\leq \sum _{i,j=1}^qa_{ij}(x)\xi _i\xi _j\leq \mu ^{-1}|\xi |^2 \end{equation*}

for a.e.

x
∈
Ω

x\in \Omega

, every

ξ
∈

R

q

\xi \in \mathbb {R}^q

, some constant

μ
\mu

. Moreover, we assume that the coefficients

a

i
j

a_{ij}

belong to the space VMO (“Vanishing Mean Oscillation”), defined with respect to the subelliptic metric induced by the vector fields

X
1

,

X
2

,
…
,

X
q

X_1,X_2,\ldots ,X_q

. We prove the following local

L

p

\mathcal {L}^p

-estimate:

‖

X
i

X
j

f
‖

L

p

(

Ω
′

)

≤
c

{

‖

L

f
‖

L

p

(
Ω
)

+

‖
f
‖

L

p

(
Ω
)

}

\begin{equation*} \left \|X_iX_jf\right \|_{\mathcal {L}^p(\Omega ’)}\leq c\left \{\left \|\mathcal {L}f\right \|_{\mathcal {L}^p(\Omega )}+\left \|f\right \|_{\mathcal {L}^p(\Omega )}\right \} \end{equation*}

for every

Ω
′

⊂⊂
Ω

\Omega ’\subset \subset \Omega

,

1
>
p
>
∞

1>p>\infty

. We also prove the local Hölder continuity for solutions to

L

f
=
g

\mathcal {L}f=g

for any

g
∈

L

p

g\in \mathcal {L}^p

with

p
p

large enough. Finally, we prove

L

p

\mathcal {L}^p

-estimates for higher order derivatives of

f
f

, whenever

g
g

and the coefficients

a

i
j

a_{ij}

are more regular.
The invariant polynomials on simple Lie superalgebras
Authors: Sergeev Alexander 
Published: July 2002

Chevalley’s theorem states that for any simple finite dimensional Lie algebra

g

\mathfrak {g}

: (1) the restriction homomorphism of the algebra of polynomials

S
(

g

∗

)
⟶
S
(

h

∗

)

S(\mathfrak {g}^*)\longrightarrow S(\mathfrak {h}^*)

onto the Cartan subalgebra

h

\mathfrak {h}

induces an isomorphism

S
(

g

∗

)

g

≅
S
(

h

∗

)

W

S(\mathfrak {g}^*)^{\mathfrak {g}}\cong S(\mathfrak {h}^*)^{W}

, where

W
W

is the Weyl group of

g

\mathfrak {g}

; (2) each

g

\mathfrak {g}

-invariant polynomial is a linear combination of the polynomials

tr
⁡
ρ
(
x

)
k

\operatorname {tr} \rho (x)^k

, where

ρ
\rho

is a finite dimensional representation of

g

\mathfrak {g}

. None of these facts is necessarily true for simple Lie superalgebras. We reformulate Chevalley’s theorem as formula

(
∗
)

(*)

below to include Lie superalgebras. Let

h

\mathfrak {h}

be the split Cartan subalgebra of

g

\mathfrak {g}

; let

R
=

R
+

∪

R
−

R=R_+\cup R_-

be the set of nonzero roots of

g

\mathfrak {g}

, the union of positive and negative ones. Set

R
~

+

=
{
α
∈

R
+

∣
−
α
∈

R
−

}

\tilde R_+=\{\alpha \in R_+\mid -\alpha \in R_-\}

. For each root

α
∈

R
~

+

\alpha \in \tilde R_+

denote by

g

(
α
)

\mathfrak {g}(\alpha )

the Lie superalgebra generated by

h

\mathfrak {h}

and the root superspaces

g

α

\mathfrak {g}_\alpha

and

g

−
α

\mathfrak {g}_{-\alpha }

. Let the image of

S
(

g

(
α

)
∗

)

g

(
α
)

S(\mathfrak {g}(\alpha )^*)^{\mathfrak {g}(\alpha )}

under the restriction homomorphism

S
(

g

(
α

)
∗

)
⟶
S
(

h

∗

)

S(\mathfrak {g}(\alpha )^*)\longrightarrow S(\mathfrak {h}^*)

be denoted by

I

α

(

h

∗

)

I^{\alpha }(\mathfrak {h}^*)

and the image of

S
(

g

∗

)

g

S(\mathfrak {g}^*)^{\mathfrak {g}}

by

I
(

h

∗

)

I(\mathfrak {h}^*)

. Then

(*)

I
(

h

∗

)
=

⋂

α
∈

R
~

+

I

α

(

h

∗

)
.

\begin{equation*} I(\mathfrak {h}^*)=\bigcap \limits _{\alpha \in \tilde R_+}I^{\alpha }(\mathfrak {h}^*).\tag *{(*)} \end{equation*}

Chevalley’s theorem for anti-invariant polynomials is also presented.
The Howe duality and the projective representations of symmetric groups
Authors: Sergeev Alexander 
Published: July 2002

The symmetric groupSk\mathfrak {S}_{k}possesses a nontrivial central extension, whose irreducible representations, different from the irreducible representations ofSk\mathfrak {S}_{k}itself, coincide with the irreducible representations of the algebraAk\mathfrak {A}_{k}generated by indeterminatesτi,j\tau _{i, j}fori≠ji\neq j,1≤i,j≤n1\leq i, j\leq nsubject to the relationsτi,j=−τj,i,τi,j2=1,τi,jτm,l=−τm,lτi,j if {i,j}∩{m,l}=∅; τi,jτj,mτi,j=τj,mτi,jτj,m=−τi,m for any i,j,l,m.\begin{gather*} \tau _{i, j}=-\tau _{j, i}, \quad \tau _{i, j}^{2}=1, \quad \tau _{i, j}\tau _{m, l}=-\tau _{m, l}\tau _{i, j}\text { if }\{i, j\}\cap \{m, l\}=\emptyset ;\ \tau _{i, j}\tau _{j, m}\tau _{i, j}=\tau _{j, m}\tau _{i, j}\tau _{j, m}=-\tau _{i, m}\; \; \text { for any } i, j, l, m. \end{gather*}Recently M. Nazarov realized irreducible representations ofAk\mathfrak {A}_{k}and Young symmetrizers by means of the Howe duality between the Lie superalgebraq(n)\mathfrak {q}(n)and the Hecke algebraHk=Sk∘ClkH_{k}=\mathfrak {S}_{k}\circ Cl_{k}, the semidirect product ofSk\mathfrak {S}_{k}with the Clifford algebraClkCl_{k}onkkindeterminates. Here I construct one more analog of Young symmetrizers inHkH_{k}as well as the analogs of Specht modules forAk\mathfrak {A}_{k}andHkH_{k}.
Measurement of the effectiveness of transitive sequence comparison, through a third 'intermediate' sequence.
Authors: Gerstein M 
Published: July 2002

Abstract
MOTIVATION: Transitive sequence matching expands the scope of sequence comparison by re-running the results of a given query against the databank as a new query. This sometimes results in the initial query sequence (Q) being related to a final match (M) indirectly, through a third, 'intermediate' sequence (Q --&gt; I --&gt; M ). This approach has often been suggested as providing greater sensitivity in sequence comparison; however, it has not yet been possible to gauge its improvement precisely. RESULTS: Here, this improvement is comprehensively measured by seeing what fraction of the known structural relationships transitive sequence matching can uncover beyond that found by normal pairwise comparison (i.e. direct linkage). The structural relationships are taken from a well-characterized test set, the scop classification of protein structure. Specifically, 2055 known structural similarities (called 'pairs') between distantly related proteins constitute the basic test set. To make the measurement of transitive matching properly, special data sets, called 'baseline sets', are derived from this. They consist of pairs of sequences that have a clear structural relationship that cannot be found by normal sequence comparison (i.e. they cannot be directly linked). Specifically, using standard sequence comparison protocols (FASTA with an e-value cut-off of 0. 001), it is found that the baseline set consists of 1742 pairs. A third intermediate sequence can link 86 of these indirectly (5%), where this third sequence is drawn from the entire, current universe of protein sequences. The number of false positives is minimal. Furthermore, when one considers only the relationships within the test set that correspond to a close structural alignment, the coverage increases considerably. In particular, 862 of the baseline set pairs fit to better than 2.6 A RMS, and transitive matching can find 62 of these (9%). AVAILABILITY: All the test data, including precise similarity values calculated from structural alignment, are available in tabular format over the Web from http://bioinfo.mbb. yale.edu/align. CONTACT: Mark.Gerstein@yale.edu
Bayesian inference on biopolymer models.
Authors: Liu J S , Lawrence C E 
Published: July 2002

Abstract
MOTIVATION: Most existing bioinformatics methods are limited to making point estimates of one variable, e.g. the optimal alignment, with fixed input values for all other variables, e.g. gap penalties and scoring matrices. While the requirement to specify parameters remains one of the more vexing issues in bioinformatics, it is a reflection of a larger issue: the need to broaden the view on statistical inference in bioinformatics. RESULTS: The assignment of probabilities for all possible values of all unknown variables in a problem in the form of a posterior distribution is the goal of Bayesian inference. Here we show how this goal can be achieved for most bioinformatics methods that use dynamic programming. Specifically, a tutorial style description of a Bayesian inference procedure for segmentation of a sequence based on the heterogeneity in its composition is given. In addition, full Bayesian inference algorithms for sequence alignment are described. AVAILABILITY: Software and a set of transparencies for a tutorial describing these ideas are available at http://www.wadsworth.org/res&res/bioinfo/
Pharmacokinetics of the 8-methoxyquinolone, moxifloxacin: tissue distribution in male rats
Authors: Siefert H. M. , Kohlsdorfer C. , Steinke W. , Witt A. 
Published: July 2002

Abstract
BAY 12-8039 (moxifloxacin-HCl) and 14C-labelled BAY 12-8039 were administered to male rats as single iv and oral doses of 4.6 and 5.0 mg/kg bodyweight respectively. The distribution of substance-associated radioactivity in the body was investigated by whole-body autoradiography. The concentrations of the unchanged compound in plasma, skin suction blister fluid and lung tissue were determined by HPLC. Whole-body autoradiography revealed distinctly higher concentrations of radioactivity in the gastrointestinal tract, urinary bladder and in most organs and tissues (e.g. kidneys, liver, spleen, lungs, various glands, cartilaginous tissues and in melanin-containing structures located in the eye, meninges and hair follicles of pigmented skin) than in blood. Radioactivity crossed the blood- brain barrier only to a small extent. The results show a high tissue affinity and a rapid and homogeneous distribution of radioactivity from blood to organs or tissues. No relevant difference in the distribution of radioactivity was found following iv and oral administration. After iv and oral dosing similar concentrations of the unchanged compound were determined in skin suction blister fluid and plasma. The concentrations of the unchanged compound in lung tissue were about three times higher than those in plasma following both iv and oral administration. The concentration–time courses for moxifloxacin in plasma and lung tissue were parallel.
Magma Mixing and Crustal Recycling Recorded in Ternary Feldspar from Compositionally Zoned Peralkaline Ignimbrite ‘A’, Gran Canaria, Canary Islands
Authors: TROLL VALENTIN R. , SCHMINCKE HANS-ULRICH 
Published: July 2002

Abstract
Miocene Ignimbrite ‘A’ on Gran Canaria contains three compositional endmember fiamme types(two rhyolites and one trachyte) each of which crystallized distinct feldspar. Various textural and compositional criteria are interpreted as reflecting a complex scenario within the magma chamber in which the crystals formed. About 25–30% of the feldspar phenocrysts contain evidence for magma mixing in the form of (1) partial to severe dissolution–resorption rims, (2) distinct zones of drastically different compositions and (3) overgrowth textures on formerly resorbed crystals. Four major types of zoning in the oligoclase to anorthoclase feldspars of ignimbrite ‘A’ include a normal and a reversely zoned type and two complexly zoned types. The feldspars with normal and reverse zonation show only minor compositional amplitudes between individual zones (ΔAb, Or ∼4%), whereas the complexly zoned types show compositional differences between zones of up to 18 mol % Ab and 20 mol % Or and are commonly associated with an internal dissolution surface. Complex zoning with large compositional amplitudes and dissolution textures is taken as evidence of crystal movements within the magma and across compositional boundaries between magma batches. A multiple ‘step-cycle’ model, involving growth and transport of a crystal into another magma batch and its return to the original host magma, is suggested by the data. Moreover, feldspars from one rhyolite compositional group are found to be substantially elevated in δ18O, suggesting an input of a high δ18O component to this rhyolite. The other endmember rhyolite appears to be related to the endmember trachyte by mainly crystal fractionation of anorthoclase feldspar. This observation is consistent with trace element and rare earth element concentrations for the magma endmembers and their feldspars, where contamination led to a depletion in incompatible trace elements and light rare earth elements in the contaminated rhyolite and its feldspar phenocrysts. We suggest that the combination of textural and compositional variation in ternary feldspar of peralkaline rhyolitic systems is well suited to reconstruct dynamic processes such as magma mixing and contamination in evolving rhyolitic magma chambers.
Conceptualization of Surrogate Decision-making Among Spokespersons for Chronically Ill Patients
Authors: Van Scoy Lauren J. , Green Michael J. , Smith Theresa , VanDyke Erika , Foy Andrew J. , Badzek Laurie , Levi Benjamin H. 
Published: December 2022

ImportanceThe value of advance care planning (ACP) has been the subject of recent debate because of mixed findings. This may be, in part, because trials presume that researchers and patient spokespersons share the same understanding of the role of a surrogate decision-maker. We explored how patient surrogates conceptualized and defined surrogate decision-making vs patient advocacy. Understanding how surrogates perceive their role in decision-making is important to avoid misinterpreting the effectiveness of ACP interventions.ObjectiveTo understand how patient spokespersons distinguish surrogate decision-making from patient advocacy.Design, Setting, and ParticipantsThis qualitative thematic analysis of a subsample of participants from a randomized clinical trial at a tertiary medical center was conducted from September 27, 2012, to June 30, 2021. Participants (n = 36) were the designated spokespersons of adult patients with severe illness who had made a surrogate decision on behalf of the patient since the last follow-up. Analysis was performed from March 21, 2021, to February 7, 2022.Main Outcomes and MeasuresSemistructured interviews examined how patient spokespersons conceptualize differences between surrogate decision-making and advocacy.ResultsThe study included 36 patient spokespersons (32 women [88.9%]; mean [SD] age, 62.1 [11.8] years) and found substantial variability in how the spokespersons conceptualized what it means to make a surrogate decision for another. A total of 10 spokespersons (27.8%) did not distinguish surrogate decision-making from advocacy. There were 5 definitions for both surrogate decision-making and advocacy. The 3 most common definitions of surrogate decision-making were (1) acting as the final decision-maker (18 [50.0%]), (2) doing what is best for the patient (8 [22.2%]), and (3) making decisions on behalf of patients so that their wishes are respected (6 [16.7%]). The 3 most common definitions of advocacy were (1) doing what is best for the patient (8 [22.2%]), (2) respecting patients’ wishes (6 [16.7%]), and (3) providing support to the patient (6 [16.7%]). The most common pairing of definitions by an individual spokesperson involved defining surrogate decision-making as being the final decision-maker, and defining advocacy as acting in the best interest of the patient (6 [16.7%]).Conclusions and RelevanceThis qualitative study found that many spokespersons perceive their roles as surrogate decision-makers differently than clinicians and researchers likely do, often conflating surrogacy with advocacy. These findings may help explain why researchers have found that ACP does not consistently improve traditional outcomes. If spokespersons do not distinguish surrogate decision-making from advocacy, then what is being reported by spokespersons and measured by clinicians and researchers may not accurately reflect the true association of ACP with outcomes.