bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Examination of the Effects of a Reservoir, Lake Ashtabula, on the Periphytic Algae in the Sheyenne River, North Dakota
Authors: Jaskowiak M. A. , Fawley K. P. , Fawley M. W. 
Published: March 2003

AbstractThe Sheyenne River is a third order stream that drains a significant portion of central and eastern North Dakota. In 1950, the Baldhill Dam was built and as a result, the reservoir, Lake Ashtabula, was formed. The periphytic algae in this river were extensively studied from 1997 to 1999. During this research, the effects of differences in environmental variables on the algal communities were assessed with Canonical Correspondence Analysis (CCA). In this analysis, the periphytic algal communities in the downstream sites appeared to be quite different from those communities found upriver of Lake Ashtabula. Other research on different rivers has shown profound changes in the algal community after a dam was built along the river. Redundancy Analysis (RDA) was used to determine if the sites downstream are more statistically similar with Lake Ashtabula than with the upstream sites. Finally, CCA was used to examine which environmental variables explain the most variance in Lake Ashtabula and the downstream sites.
Apoglosseae Trib. Nov. (Delesseriaceae, Rhodophyta) Based on Two Molecular Datasets and Cystocarp Development
Authors: Lin S.‐M. , Fredericq S. , Hommersand M. H. 
Published: March 2003

AbstractThe genus Apoglossum J. Agardh has traditionally been placed in the tribe Delesserieae. Our morphological observations on Apoglossum and the ‘Delesseria’ species belonging to the resurrected genus Paraglossum from the Southern Hemisphere show that they possess a distinct procarp. Apoglossum has two one‐celled sterile groups that divide after fertilization and Paraglossum consists of two one‐celled sterile groups that do not divide after fertilization, but in which the nuclei divide to produce four to eight nuclei in the undivided sterile groups. In contrast, the procarp in D. sanguinea, the type species of the tribe Delesserieae, consists of two 2–6‐celled sterile groups before fertilization and the number of sterile cells double after fertilization. The development of the carposporophyte in both Apoglossum and Paraglossum is shown to be unique in the subfamily Delesserioideae. The pit connections between the segments of the gonimoblast filaments broaden without fusion and secondary carposporangia are produced. This pattern is absent in other members of the Delesserioideae, but has been reported for the tribes Myriogrammeae and Schizoserideae in the new subfamily Phycodryoideae Lin, Fredericq et Hommersand. Based on both LSU rDNA and rbcL sequence analyses, the Delesserieae is restricted to species of Delesseria and Membranoptera from the North Atlantic and North Pacific Oceans. In contrast, the species of Apoglossum and Paraglossum form a distinct cluster having a center of distribution in the Southern Hemisphere with only a few species, such as A. ruscifolium, reaching the Northern Hemisphere. In this study, details of postfertilization development leading to the cystocarp are illustrated for the type species of Apoglossum and Paraglossum and a new tribe, the Apoglosseae, is recognized in the Delesseriaceae.
The Roots of Land Plants: Recent Research on Early Diverging Lineages in the Evolution of Higher Drier Algae
Authors: McCourt R. M. , Karol K. G. , Delwiche C. F. 
Published: March 2003

AbstractRecent multigene phylogenetic analyses of charophycean algae sensu Mattox and Stewart have advanced our understanding of the relationships of the green algae that are most closely related to land plants. Several clades of green algae are monophyletic with land plants (i.e. liverworts, mosses, nonvascular and vascular plants that arose from an aquatic ancestor) to the exclusion of other green algae: Mesostigma (a flagellate unicell); the Chlorokybales (small packets of cells); Klebsormidiales (unbranched filaments); Zygnematales (conjugating unicells, filaments, and colonies); Coleochaetales (filamentous and parenchymatous thalli); and Charales (branched filamentous thalli with complex nodal structure). The morphological and molecular diversity of the extant members of this nearly exclusively freshwater clade is remarkable. Moreover, the taxon diversity within clades is highly asymmetric, having yielded several distinctive albeit small groups of green algae, as well as one of the major evolutionary success stories on earth, viz. land plants. The most recent analysis (Karol et al. (2001) Science 294 : 2351–2353) of four genes from plastid, mitochondrial, and nuclear compartments strongly support the sister relationships of Charales (stoneworts) to the most primitive land plants. The analysis also shows that within this clade there has been a trend toward increasing complexity of thallus form (from unicells, to filaments, to branching and parenchymatous thalli) and reproduction (absence of sexual reproduction to iso‐ or anisogamy, to oogamy). Although the major clades mentioned above are well supported by molecular analyses, relationships among these groups are less well‐resolved, especially for the Klebsormidiales, Chlorokybales, and Mesostigma. This paper reviews the morphological and molecular evidence for the relationships among and within these groups. More sequence data from a broader sampling of taxa at the base of the charophyceans (including perhaps some algae not now known to be charophytes) should provide a clearer picture of the evolution of this group and the reasons for its success.
Characterization of sufB Sequences from Nongreen Photoautotrophs
Authors: Misner I. J. , Bailey J. C. , Freshwater D. W. 
Published: March 2003

AbstractPartial sequences for the hypothetical chloroplast frame 24 (ycf24) were determined for 13 species of algae representing the classes Bacillariophyceae, Chrysophyceae, Pelagophyceae, Pinguiophyceae, Prymnesiophyceae, Raphidophyceae, and Xanthophyceae. In many databases ycf24 is considered an ATP‐binding cassette (ABC) transporter. Our analyses of translated amino acid sequences demonstrate that these sequences lack Walker A and B boxes, a conserved ABC signature sequence motif, and transmembrane domains that characterize ABC transporters. Our data, as well as those of others, convincingly indicate that ycf24 is not an ABC transporter and is instead homologous to the sufB gene first described from prokaryotes. The function of the sufB gene product in eukaryotic plastids is not known with certainty but it likely plays a key role in iron–sulfur (2Fe−2S) cluster formation. Our data, unpublished results and database searches imply that sufB is plastid encoded in the ‘red’ plastid lineage, but has been transferred to the nucleus or lost within the streptophyte lineage. Phylogenetic analyses of all available eucaryotic sufB sequences indicate that this gene is a useful marker for tracing the ancestry of plastids and their hosts. For example, our sufB analyses indicate that the 35‐Kb circular plastid genome of Plasmodium falciparum is a member of the ‘red’, not ‘green’, plastid lineage and was acquired via secondary endosymbiosis. Our results also support the hypothesis that, despite their similarities, the plastids of prymnesiophytes and heterokont algae were independently obtained by separate secondary endosymbiotic events.
Characterization of Macroalgal Epiphytes on Thalassia Testudinum in Tampa Bay, Florida
Authors: Cho T. O. , Fredericq S. , Yates K. K. 
Published: March 2003

AbstractBlooms of seagrass epiphytes have potentially important economic and ecological consequences in Tampa Bay, one of the Gulf of Mexico's largest estuaries. As part of a Tampa Bay pilot study to monitor the impact of environmental stresses, precise characterization of epiphyte diversity is required for efficient management of affected resources, and thus may be used as a rational basis for assessment of ecosystem health. Fixed monitoring sites were selected north of Port Manatee, composed of dense and sparse Thalassia testudinum seagrass sites. A total of 13 epiphytic species encompassing green, brown and red macroalgae were manually collected in May 2001 from dense seagrass beds versus nine species from sparse beds. Epiphytes only collected in the dense beds were Enteromorpha flexuosa, Sphacelaria rigidula, Ceramium byssoideum, and Herposiphonia tenella; epiphytes only occurring in the sparse beds were Griffithsia and Stylonema alsidii. A correlation seems to emerge among attachment mode of epiphyte to host, presence of cortication and epiphyte length. A main goal of this ongoing study is the determination of indicator species for both healthy and stressed seagrass bed environments using both taxonomic and gene‐sequencing techniques.
Sleep Apnea, Delirium, Depressed Mood, Cognition, and ADL Ability After Stroke
Authors: Sandberg Olov , Franklin Karl A. , Bucht Gösta , Gustafson Yngve 
Published: March 2003

OBJECTIVES: The incidence of sleep apnea and stroke increases with age. The aim of this study was to investigate the presence of sleep apnea after stroke and its relationship to delirium, depressed mood, cognitive functioning, ability to perform activities of daily living (ADLs), and psychiatric and behavior symptoms.DESIGN: Cross‐sectional study.SETTING: Geriatric stroke rehabilitation unit.PARTICIPANTS: 133 patients (78 women and 55 men, mean age 77.1 ± 7.7 years) consecutively admitted to a geriatric stroke rehabilitation unit.MEASUREMENTS: All patients underwent overnight respiratory sleep recordings at 23 ± 7 days (range 11 to 41 days) after suffering a stroke. The patients were assessed using the Organic Brain Syndrome Scale, Montgomery‐Åsberg‐Depression‐Rating Scale, Mini‐Mental State Examination (MMSE), and Barthel‐ADL Index. Sleep apnea was defined as an apnea‐hypopnea index (AHI) of 10 or more.RESULTS: The median of the AHI for the studied sample (N = 133) was 13 (range 0–79; interquartile range 6–28). Fifty‐nine percent fulfilled the criteria for sleep apnea; 52% with first‐ever stroke had sleep apnea. More patients with sleep apnea than without were delirious, depressed, or more ADL‐dependent. Sleep apnea patients also had a higher frequency of ischemic heart disease and had more often suffered from an earlier cerebral infarction. Multivariate analysis showed that obesity, low ADL scores, ischemic heart disease, and depressed mood were independently associated with sleep apnea. Low ADL scores, apnea‐related hypoxemia, body mass index ≤27, and impaired vision were independently associated with delirium. The presence of sleep apnea was not associated with any specific type of stroke or location of the brain lesion.CONCLUSIONS: Sleep apnea is common in stroke patients and is associated with delirium, depressed mood, latency in reaction and in response to verbal stimuli, and impaired ADL ability. We suggest a trial investigating whether delirium, depressed mood, and ADL ability improve with nasal continuous positive airway pressure treatment of sleep apnea in stroke patients.
Weight Change in Old Age and its Association with Mortality
Authors: Newman Anne B. , Yanez David , Harris Tamara , Duxbury Andrew , Enright Paul L. , Fried Linda P. ,   for the Cardiovascular Study Research Group
Published: March 2003

OBJECTIVES:Previous studies of weight change and mortality in older adults have relied on self‐reported weight loss, have not evaluated weight gain, or have had limited information on health status. Our objective was to determine whether 5% weight gain or loss in 3 years was predictive of mortality in a large sample of older adults.DESIGN:Longitudinal observational cohort study.SETTING:Four U.S. communities.PARTICIPANTS:Four thousand seven hundred fourteen community‐dwelling older adults, age 65 and older.MEASUREMENTS:Weight gain or loss of 5% in a 3‐year period was examined in relationship to baseline health status and interim health events. Risk for subsequent mortality was estimated in those with weight loss or weight gain compared with the group whose weight was stable.RESULTS:Weight changes occurred in 34.6% of women and 27.3% of men, with weight loss being more frequent than gain. Weight loss was associated with older age, black race, higher weight, lower waist circumference, current smoking, stroke, any hospitalization, death of a spouse, activities of daily living disability, lower grip strength, and slower gait speed. Weight loss but not weight gain of 5% or more was associated with an increased risk of mortality that persisted after multivariate adjustment (Hazard ratio (HR) = 1.67, 95% CI = 1.29–2.15) and was similar in those with no serious illness in the period of weight change. Those with weight loss and low baseline weight had the highest crude mortality rate, although the HR for weight loss was similar for all tertiles of baseline weight and for those with or without a special diet, compared with those whose weight was stable.CONCLUSIONS:This study confirms that even modest decline in body weight is an important and independent marker of risk of mortality in older adults. J Am Geriatr Soc 49:1309–1318, 2001.
Leg Muscle Mass and Composition in Relation to Lower Extremity Performance in Men and Women Aged 70 to 79: The Health, Aging and Body Composition Study
Authors: Visser Marjolein , Kritchevsky Stephen B. , Goodpaster Bret H. , Newman Anne B. , Nevitt Michael , Stamm Elizabeth , Harris Tamara B. 
Published: March 2003

OBJECTIVES: The loss of muscle mass with aging, or sarcopenia, is hypothesized to be associated with the deterioration of physical function. Our aim was to determine whether low leg muscle mass and greater fat infiltration in the muscle were associated with poor lower extremity performance (LEP).DESIGN: A cross‐sectional study, using baseline data of the Health, Aging and Body Composition study (1997/98).SETTING: Medicare beneficiaries residing in ZIP codes from the metropolitan areas surrounding Pittsburgh, Pennsylvania, and Memphis, Tennessee.PARTICIPANTS: Three thousand seventy‐five well‐functioning black and white men and women aged 70 to 79.MEASUREMENTS: Two timed tests (6‐meter walk and repeated chair stands) were used to measure LEP. Muscle cross‐sectional area and muscle tissue attenuation (indicative of fat infiltration) were obtained from computed tomography scans at the midthigh. Body fat was assessed using dual‐energy x‐ray absorptiometry.RESULTS: Blacks had greater muscle mass and poorer LEP than whites. Black women had greater fat infiltration into the muscle than white women. After adjustment for clinic site, age, height, and total body fat, smaller muscle area was associated with poorer LEP in all four race‐gender groups. (Regression coefficients, expressed per standard deviation (±55 cm2) of muscle area, were 0.658 and 0.519 in white and black men and 0.547 and 0.435 in white and black women, respectively, P < .01.) In addition, reduced muscle attenuation—indicative of greater fat infiltration into the muscle—was associated with poorer LEP, independent of total body fat and muscle area. (Regression coefficients per standard deviation (= 7 Hounsfield Units) of muscle attenuation were 0.292 and 0.224 in white and black men, and 0.193 and 0.159 in white and black women, respectively, P < .05). The most important body composition components related to LEP were muscle area in men and total body fat in women. Results were similar after additional adjustment for lifestyle factors and health status. No interactions between race and muscle area (P> .7) or between race and muscle attenuation (P> .2) were observed.CONCLUSION: Smaller midthigh muscle area and greater fat infiltration in the muscle are associated with poorer LEP in well‐functioning older men and women.
Looking at the Relationship Between Hemoglobin Concentration and Prevalent Mobility Difficulty in Older Women. Should the Criteria Currently Used to Define Anemia in Older People be Reevaluated?
Authors: Chaves Paulo H. M. , Ashar Bimal , Guralnik Jack M. , Fried Linda P. 
Published: March 2003

OBJECTIVES: The World Health Organization (WHO) and other currently used criteria for defining anemia in older women are mainly based on statistical distribution considerations. To explore their clinical appropriateness, we evaluated the relationship between hemoglobin (Hb) concentration, prevalent mobility difficulty, and the Summary Performance Score (SPS).DESIGN: Cross‐sectional study.SETTING: Two population‐based studies, the Women's Health and Aging Studies I and II, Baltimore, Maryland.PARTICIPANTS: Six hundred thirty‐three community‐dwelling women aged 70 to 80 with Hb levels obtained within 90 days from baseline assessment.MEASUREMENTS: Mobility difficulty (self‐reported difficulty walking one‐quarter of a mile or climbing 10 steps (primary outcome)). SPS, a performance‐based summary measure of lower extremity function that combines the results of walking, chair stands, and balance tests (secondary outcome).RESULTS: Mobility difficulty prevalence was not constant within the WHO “normal” Hb range (12.0–16.0 g/dL). For example, a Hb of 13.5 g/dL was associated with a significantly lower mobility difficulty prevalence than a Hb of 12.0 g/dL (OR = 0.68, 95% CI = 0.47–0.93), even after adjustment for chronic diseases and other relevant health indicators. A consistent trend of improvement in performance‐based scores with increasing Hb categories less than 12.0 g/dL, 12.0 to 13.0g/dL, and 13.0–14.0 g/dL was observed.CONCLUSION: Our findings raise two hypotheses: (1) Hb currently perceived as “mildly‐low” and even “low‐normal” might have an independent, adverse effect on mobility function, and (2) Hb of 12.0 g/dL might be a suboptimal criterion for defining anemia in older women. Formal testing of these hypotheses might prove relevant for anemia‐ and mobility disability–related clinical decision‐making.
Age‐Related Differences in Lower Extremity Power After Support Surface Perturbations
Authors: Hall Courtney D. , Jensen Jody L. 
Published: March 2003

OBJECTIVES: The purpose of this study was to examine a comprehensive measure relating to the ability to generate, absorb, and transfer mechanical energy introduced by a perturbation. It was hypothesized that this measure would reveal age‐related differences leading to different balance recovery responses (i.e., feet‐in‐place and compensatory step).DESIGN: Cross‐sectional, descriptive study.SETTING: The Motor Control Laboratory at the University of Oregon.PARTICIPANTS: Eighteen younger (aged 18–35) and 21 older (aged 65–85) women received forward and backward support surface translations of varying amplitudes and velocities.MEASUREMENTS: Lower extremity peak positive joint power and peak negative muscle power were examined at the largest perturbation in which a feet‐in‐place response was used and the subsequent perturbation where a step occurred. Peak positive joint power depicts the maximum rate of passive transfer of energy into a segment and is indicative of the maximum destabilization of that segment. Peak negative muscle power is the maximum rate of energy absorption by muscle, which reduces the effect of the perturbation on the segment.RESULTS: After a backward perturbation, there was a significant main effect of age for muscle power and a significant main effect of response type for joint power. For the forward condition, there was a significant main effect of response type for muscle power only.CONCLUSIONS: The mechanical reason for the emergence of the compensatory step after support‐surface perturbations is clear; the feet‐in‐place response is energetically more demanding than the compensatory step. The energy analysis suggests a mechanical basis as one reason for older adults' reliance on the compensatory step: older adult muscles absorb less energy. The results of this study also highlight the importance of the proximal knee and hip musculature versus the distal ankle musculature.
Do Older Adults Expect to Age Successfully? The Association Between Expectations Regarding Aging and Beliefs Regarding Healthcare Seeking Among Older Adults
Authors: Sarkisian Catherine A. , Hays Ron D. , Mangione Carol M. 
Published: March 2003

OBJECTIVES: To measure expectations regarding aging among community‐residing‐older adults, identify characteristics associated with having low expectations regarding aging, and examine whether expectations regarding aging are associated with healthcare‐seeking beliefs for age‐associated conditions.DESIGN: Self‐administered mail survey.SETTING: Greater Los Angeles.PARTICIPANTS: Four hundred twenty‐nine of 588 (73%) randomly selected community‐residing adults aged 65 to 100 (mean age 76) cared for by 20 primary care physicians; 54% were women, and 76% were white.MEASUREMENTS: The Expectations Regarding Aging Survey, a validated survey measuring expectations regarding aging; 13 items measuring care seeking beliefs; and validated measures of health status.RESULTS: More than 50% of participants felt it was an expected part of aging to become depressed, to become more dependent, to have more aches and pains, to have less ability to have sex, and to have less energy. After adjusting for sociodemographic and health characteristics using multivariate regression, older age was independently associated with lower expectations regarding aging (P < .001), as was having lower physical and mental health‐related quality of life. Having lower expectations regarding aging was independently associated with placing less importance on seeking health care (P = .049).CONCLUSIONS: Most older adults in this sample did not expect to achieve the model of successful aging in which high cognitive and physical functioning is maintained. Older age was independently associated with lower expectations regarding aging. Furthermore, having low expectations regarding aging was independently associated with not believing it important to seek health care.
Outcomes of Pain in Frail Older Adults With Dementia
Authors: Brummel‐Smith Kenneth , London Marla R. , Drew Nicholas , Krulewitch Harry , Singer Clifford , Hanson Lynn 
Published: March 2003

OBJECTIVES: To describe the outcomes of pain in cognitively impaired older adults in a Program of All‐inclusive Care for older people (PACE) setting and to determine whether pain and psychotropic drug use, behavioral disturbances, hospital, nursing facility, and emergency department use, or mortality increases with the level of pain reported.DESIGN: Retrospective review of an observational cohort of patients with dementia.SETTING: A first‐generation PACE program located in Portland, Oregon. Patients with the diagnosis of dementia had been assessed for pain in a prior study.PARTICIPANTS: One hundred fifty‐four cognitively impaired subjects.MEASUREMENTS: Standardized pain assessments were administered to cognitively impaired subjects between June and October 1998. After the pain assessment, information about mortality and healthcare use, including use of medication, was collected and analyzed. Subjects who reported moderate to severe pain were compared with demented subjects who reported no or mild pain.RESULTS: There were no differences in patient characteristics (age, sex, functional limitations, disruptive behaviors, and incontinence), medications (pain and psychotropic), use (hospital, nursing home, or emergency department visit), or mortality by level of pain alone or by levels of pain and dementia together.CONCLUSIONS: The study did not demonstrate that a single point‐in‐time measurement of pain in demented persons was associated with an increased rate of behavioral problems, narcotic use, or hospital or emergency department use over the following year. Prospective studies are needed that measure pain over time to determine more accurately the relationship between pain and negative outcomes in dementia.