bluuebunny/crossref_metadata_2025 huggingface dataset:
What young children do and do not know about the spelling of inflections and derivations
Authors: Deacon S. Hélène , Bryant Peter
Published: October 2005

Morphemes have a powerful impact on the spellings of words in English. We report on two experiments examining young children's knowledge of the effect of suffix morphemes on spelling. In Experiment 1, 5‐ to 8‐year‐olds demonstrated awareness of the role of inflections, but not derivations in spelling. Experiment 2 examined whether children might show an understanding of the impact of derivations on spelling when they are provided with the specific spelling pattern. There was support for this idea; 7‐ to 10‐year‐old children took advantage of the derivations that were given to spell other derivations, but not the endings of control words. The results of these experiments suggest that young children are aware of the role that suffixes play in determining spelling, but that there are limits, such as those imposed by spelling difficulty, that constrain the execution of this knowledge. These findings provide new insights into current theoretical debates on spelling development.
Ambiguous benefits: the effect of bilingualism on reversing ambiguous figures
Authors: Bialystok Ellen , Shapero Dana
Published: October 2005

Two studies are reported in which monolingual and bilingual children, approximately 6 years old, attempted to identify the alternative image in a reversible figure. In both studies, bilingual children were more successful than monolinguals in seeing the other meaning in the images. In the first study, there was no relation between the ability to reverse the interpretation and performance on the children's embedded figures task, a task that superficially appeared to involve similar processes. The second study replicated this finding but showed that performance was strongly related to success in the post‐switch phase of the dimensional change card sort task. In both cases, the meaning of an image must be reassigned, and bilinguals were better in both these tasks.
A longitudinal investigation of visual event‐related potentials in the first year of life
Authors: Webb Sara J. , Long Jeffrey D. , Nelson Charles A.
Published: October 2005

The goal of the current study was to assess general maturational changes in the ERP in the same sample of infants from 4 to 12 months of age. All participants were tested in two experimental manipulations at each age: a test of facial recognition and one of object recognition. Two sets of analyses were undertaken. First, growth curve modeling with mixed models was used to examine trajectories of development and possible differences in trajectories based on recognition memory (novel versus familiar) and/or stimulus‐specific memory (face versus object recognition). Our results suggest that the Pb, Nc and Slow Wave components change significantly in terms of amplitude and latency over the first year of life. Pb amplitude showed a significant non‐linear increase over time, whereas Pb latency showed a significant linear decrease over time with a plateau beginning at 10 months. Nc amplitude showed a significant linear decrease over time (i.e. a stronger negative value), whereas Nc latency showed a significant linear decrease over time, with a plateau beginning at 8 months. Second, to relate our findings to those reported in the literature, we examined the effects of memory and stimulus and their combination. Differences between recognition memory and stimulus specific memory were found in the responses to familiar and novel faces and objects for all three components, although the pattern differed across the five ages. These results have implications for future studies that involve the recording of the visual ERP, and point to the advantages of growth curve modeling in examining longitudinal data to account for non‐linear development.
Three‐month‐olds, but not newborns, prefer own‐race faces
Authors: Kelly David J. , Quinn Paul C. , Slater Alan M. , Lee Kang , Gibson Alan , Smith Michael , Ge Liezhong , Pascalis Olivier
Published: October 2005

Adults are sensitive to the physical differences that define ethnic groups. However, the age at which we become sensitive to ethnic differences is currently unclear. Our study aimed to clarify this by testing newborns and young infants for sensitivity to ethnicity using a visual preference (VP) paradigm. While newborn infants demonstrated no spontaneous preference for faces from either their own‐ or other‐ethnic groups, 3‐month‐old infants demonstrated a significant preference for faces from their own‐ethnic group. These results suggest that preferential selectivity based on ethnic differences is not present in the first days of life, but is learned within the first 3 months of life. The findings imply that adults’ perceptions of ethnic differences are learned and derived from differences in exposure to own‐ versus other‐race faces during early development.
Headache in Ischemic Cerebrovascular Disease. Part II: Mechanisms and Predictive Value
Authors: Mitsias Panayiotis , Ramadan Nabih M
Published: October 2005

In part I, the prevalence and clinical characteristics of headache in ischemic cerebrovascular disease were reviewed. In this part, we describe the potential mechanisms of head pain and the value of the headache symptom as a predictor of stroke type, location and vascular territory.
Non-Migraine Headache Across the Menstrual Cycle in Women With and Without Premenstrual Syndrome
Authors: Keenan PA , Lindamer LA
Published: October 2005

Fluctuation of estrogen levels across the menstrual cycle influences migraine headache. In this study, 53 women documented prospectively the incidence and severity of headache daily for an average of three menstrual cycles. Seven of the women met the criteria established by the International Headache Society for migraine with or without aura, while the remaining 46 women failed to do so. Chi-square analysis revealed that, overall, the incidence of non-migraine headache was dependent on day of the cycle (χ2 [1,66] = 247.7, p < 0.001), with more headaches occurring during the perimenstrual phase. The 46 women without migraine were further classified according to NIMH criteria into PMS ( N= 26) and non-PMS groups (n = 26). An association between headache and menstrual cycle phase was noted for both groups ( p < 0.001), although the incidence of severe headache was greater for the PMS women, during both the perimenstrual and intermenstrual phases. Both groups experienced an increase in severe headaches during the perimenstrual phase. The PMS women peaked on the day prior to menstruation, while the non PMS women peaked on the first day of menstruation. There did not appear to be an overall difference in the reporting of mild headache across the cycle between women with or without PMS. These findings suggest that (a) severe headache which does not meet the criteria for migraine with or without aura also may be menstrually related in women with and without PMS and; (b) the as yet unidentified physiological mechanism predisposing some women to PMS may also render them susceptible to more frequent, severe, non-migraine headaches both during the perimenstrual phase and throughout the entire menstrual cycle.
Cardiovascular Reflexes in Patients With Vascular Headache
Authors: Martín Rosario , Ribera Cristina , Moltó Jose Manuel , Ruiz Carolina , Galiano Luz , Matías-Guiu Jorge
Published: October 2005

We have investigated the autonomic function of 75 patients with migraine by examining cardiovascular reflex function. The results were compared with those of 78 healthy volunteers. Measurements were made between attacks. Patients with migraine showed a smaller heart-rate response to deep breathing but a greater heart-rate response and higher blood pressure to standing when compared to controls. Migraine patients had a higher percentage of established sympathetic lesions (51% vs 17%) and severe (25% vs 5%) or atypical (24% vs 11.5%) global autonomic dysfunction. No significant differences were found among patients with migraine with aura, migraine without aura, and migraine with prolonged aura. Our findings indicate that patients with migraine have sympathetic hypofunction.
Presentation of a New Instrument: The Diagnostic Headache Diary
Authors: Russell Michael Bjørn , Rasmussen Birthe Krogh , Brennum Jannick , Iversen Helle Klingenberg , Jensen Rigmor Agnethe , Olesen Jes
Published: October 2005

A new instrument, the Diagnostic Headache Diary, based on the operational diagnostic criteria of the International Headache Society (IHS), was tested in 61 migraine patients from a headache research clinic using the clinical diagnosis (IHS criteria) for comparison. All patients kept the diary for one to eight months. The clinical and diary diagnosis of migraine with and without aura was the same in, respectively, 72 and 87% of the patients. Nausea, photophobia and phonophobia tended to be more pronounced at the clinical interview. The diary identified 20 more cases of episodic tension-type headache and 15 fewer cases of chronic tension-type headache than the clinical interview. Two blinded observers always made the same IHS diagnoses when interpreting the diagnostic headache diary. A combination of a clinical interview and the diagnostic headache diary gives a qualitatively and quantitatively more precise diagnosis than a clinical interview alone.
The 5-HT1-Like Agonist Sumatriptan has a Significant Effect in Chronic Tension-Type Headache
Authors: Brennum Jannick , Kjeldsen Michel , Olesen Jes
Published: October 2005

Subcutaneous treatment of chronic tension-type headache with 2 mg and 4 mg sumatriptan, a selective 5-hydroxytryptamine1-like receptor agonist, was compared with placebo in a double-blind crossover study of 36 patients. The effect was evaluated using a 6-point verbal relief rating scale and by visual analog scale ratings of headache intensity before and for 2 h after treatment. Sumatriptan induced a modest but significantly greater headache relief than placebo, whereas no significant difference was found between the two doses of sumatriptan. Headache relief following sumatriptan was significant after 60 min and still seemed to be increasing after 120 min when the examination terminated. Three possible mechanisms of action of sumatriptan in tension-type headache are discussed.
Headache Following Carotid Endarterectomy: A Prospective Study
Authors: Tehindrazanarivelo Alain Djacoba , Lutz Gina , Petitjean Christian , Bousser Marie-Germaine
Published: October 2005

The occurrence of headache in the 28 days following surgery was studied in 50 consecutive patients (14F and 36M, mean aged 70 years) who underwent carotid endarterectomy for atheromatous carotid stenosis. Thirty-one patients (62%) reported headache. Headache occurred in the first five days after surgery in 87% of cases. Its characteristics and temporal profile were highly variable but it was mostly bilateral (74%), mild or moderate (78%), requiring no treatment (77%). No correlation was found between the occurrence of headache and degree of stenosis, intraoperative characteristics and past history of headache. In none of our patients was severe ipsilateral headache, cerebral hyperperfusion syndrome, or cluster-like hemicrania encountered and only five patients met the IHS criteria for post-endarterectomy headache. Post-endarterectomy headache is frequent when specifically looked for and is therefore not a single entity. The present IHS criteria are unsatisfactory and should be modified accordingly.
Raised Plasma Endothelin During Acute Migraine Attack
Authors: Färkkilä Markus , Palo Jorma , Saijonmaa Outi , Fyhrquist Frej
Published: October 2005

Endothelins are the most potent vasoconstrictor peptides known. Plasma endothelin (ET-1) concentrations were measured in eight migraine patients (mean age 44.5 years), two during an acute migraine attack with aura and six during an attack without aura. The mean ET-1 values were elevated in all migraine patients above the range of normal subjects, and were 10.6 (range 6.0–16.0) pg/ml in migraine patients and 3.8 (range 0.7–5.8) pg/ml in controls. We hypothesize that ET-1 may constrict cerebral vessels during the initial stage of the migraine attack.
Transcranial Doppler Ultrasonic Features in Chronic Tension-Type Headache
Authors: Wallasch Thomas-Martin
Published: October 2005

We studied vascular features in patients suffering from chronic headache of the tension-type by means of transcranial Doppler ultrasound (TCD). Blood flow velocities of the basal cerebral arteries and the submandibular extracranial part of the internal carotid artery were compared between 20 chronic tension-type headache sufferers and the same number of age- and sex-matched control subjects. There were no significant differences of ultrasonic features between the groups. Changes in blood flow velocities do not seem to be involved in the pathogenetic mechanisms of chronic tension-type headache.
Shortlasting, Unilateral, Neuralgiform Headache Attacks With Conjunctival Injection and Tearing (SUNCT Syndrome): V. Orbital Phlebography
Authors: Kruszewski Piotr
Published: October 2005

We studied six patients with SUNCT, a unilateral headache syndrome with shortlasting attacks and ipsilateral autonomic phenomena with orbital phlebography and MRI. All but one orbital phlebogram showed abnormalities on the headache side (in one patient bilaterally), involving the superior ophthalmic vein or/and the cavernous sinus. No systematic changes were demonstrated on MRI. The phlebography findings were similar to those observed in the Tolosa-Hunt syndrome and in cluster headache.
Adenosine A2A receptor stimulation potentiates nitric oxide release by activated microglia
Authors: Saura Josep , Angulo Ester , Ejarque Aroa , Casadó Vicent , Tusell Josep M. , Moratalla Rosario , Chen Jiang‐Fan , Schwarzschild Michael A. , Lluis Carme , Franco Rafael , Serratosa Joan
Published: October 2005

The absence of adenosine A2A receptors, or its pharmacological inhibition, has neuroprotective effects. Experimental data suggest that glial A2A receptors participate in neurodegeneration induced by A2A receptor stimulation. In this study we have investigated the effects of A2A receptor stimulation on control and activated glial cells. Mouse cortical mixed glial cultures (75% astrocytes, 25% microglia) were treated with the A2A receptor agonist CGS21680 alone or in combination with lipopolysaccharide (LPS). CGS21680 potentiated lipopolysaccharide‐induced NO release and NO synthase‐II expression in a time‐ and concentration‐dependent manner. CGS21680 potentiation of lipopolysaccharide‐induced NO release was suppressed by the A2A receptor antagonist ZM‐241385 and did not occur on mixed glial cultures from A2A receptor‐deficient mice. In mixed glial cultures treated with LPS + CGS21680, the NO synthase‐II inhibitor 1400W abolished NO production, and NO synthase‐II immunoreactivity was observed only in microglia. Binding experiments demonstrated the presence of A2A receptors on microglial but not on astroglial cultures. However, the presence of astrocytes was necessary for CGS21680 potentiating effect. In light of the reported neurotoxicity of microglial NO synthase‐II and the neuroprotection of A2A receptor inhibition, these data suggest that attenuation of microglial NO production could contribute to the neuroprotection afforded by A2A receptor antagonists.
Normal values of pulmonary capillary wedge pressure and the blood pressure response to the Valsalva manoeuvre in healthy elderly subjects
Authors: Remmen Jaap J. , Aengevaeren Wim R. M. , Verheugt Freek W. A. , Jansen René W. M. M.
Published: October 2005

The blood pressure response to the Valsalva manoeuvre is related to pulmonary capillary wedge pressure (PCWP) and can be used to diagnose heart failure. However, this has never been studied specifically in the elderly, in whom the prevalence of heart failure is highest. Furthermore, normal values of the Valsalva manoeuvre are lacking. We aimed to obtain normal values of PCWP and the blood pressure response to the Valsalva manoeuvre in elderly subjects. Therefore, 28 healthy subjects, aged 70 ± 4 years, performed Valsalva manoeuvres before and after anti‐G garment inflation, which was used for temporary increase of PCWP. Before inflation, PCWP was 9·8 ± 1·9 mmHg in supine and 8·9 ± 2·1 in semi‐recumbent position. From the blood pressure response, measured with Finapres, the systolic blood pressure ratio (SBPR), pulse pressure ratio (PPR), stroke volume ratio (SVR) and heart rate ratio (HRR) were calculated. In supine position, SBPR was 0·76 ± 0·11, PPR 0·51 ± 0·16, SVR 0·42 ± 0·11, and HRR 1·17 ± 0·12. Semi‐recumbently, SBPR was 0·74 ± 0·10, PPR 0·46 ± 0·14, SVR 0·41 ± 0·10, and HRR 1·24 ± 0·23. After inflation of the anti‐G garment, the areas under the Receiver Operator Characteristics curves of SBPR, PPR and SVR for elevated (≥15 mmHg) PCWP were >0·85 in supine position. In conclusion, this is the first study to obtain normal values of the blood pressure response to the Valsalva manoeuvre and PCWP in healthy elderly subjects, which is essential for the interpretation of patient data. The Valsalva manoeuvre showed significant discriminatory power in the detection of elevated PCWP, which underscores its potential in the non‐invasive diagnosis of heart failure.
The effects of left ventricular hypertrophy on the respiratory changes in transmitral Doppler flow patterns of hypertension patients
Authors: Hsu Chih‐Hsin , Tsai Wei‐Chuan , Tsai Liang‐Miin , Lin Chih‐Chan , Chen Ju‐Yi , Huang Yao‐Yi , Chao Ting‐Hsing , Liu Ping‐Yen , Chen Jyh‐Hong
Published: October 2005

Background:  Left ventricular early diastolic fillings can be reduced by inspiration. However, the effects of left ventricular hypertrophy on such changes have not been studied before. This study was undertaken to investigate whether respiratory changes in transmitral Doppler flow were affected by left ventricular hypertrophy in hypertension patients.

Methods:  Eighty‐three patients (mean age 46 ± 8 years, 49 males) with untreated essential hypertension were included in this study. Transmitral Doppler flow velocity was measured both at end‐expiration and end‐inspiration. Left ventricular mass was measured by M‐mode echocardiography. We divided patients into two groups based on the presence of left ventricular hypertrophy or not.

Results:  Twenty‐one patients were diagnosed to have left ventricular hypertrophy. In patients without left ventricular hypertrophy, the peak early filling velocity decreased significantly (from 74 ± 15 to 71 ± 18 cm s−1, P = 0·003), the peak atrial velocity increased significantly (from 65 ± 17 to 74 ± 15 cm s−1, P<0·001) and the early filling to atrial velocity ratio decreased significantly (from 1·2 ± 0·3 to 1·1 ± 0·3, P<0·001) from end‐expiration to end‐inspiration. In patients with left ventricular hypertrophy, the parameters of transmitral Doppler flow pattern did not change during respiration.

Conclusion:  Respiratory changes in the transmitral Doppler flow velocity are blunted by left ventricular hypertrophy in hypertension patients. This phenomenon is probably contributed by the increased left ventricular wall stiffness in the left ventricular hypertrophy.
Physiological determinants of the variation in left ventricular mass from early adolescence to late adulthood in healthy subjects
Authors: Cain Peter A. , Ahl Ragnhild , Hedstrom Erik , Ugander Martin , Allansdotter‐Johnsson Ase , Friberg Peter , Marild Staffan , Arheden Hakan
Published: October 2005

Background:  The physiological determinants of left ventricular mass (LVM) measured by cardiac magnetic resonance (CMR) imaging are not well defined as prior investigators have studied either adults or adolescents in isolation or have not strictly excluded hypertension or accounted for the effects of exercise habits, haemodynamic, demographic, or body shape characteristics.

Methods:  A total of 102 healthy volunteers (12–81 years, 53 males) underwent CMR. All parameters [unstandardized and adjusted for body surface area (BSA)] were analysed according to gender and by adolescence versus adulthood (adolescents <20 years, adults ≥20 years). The influence of haemodynamic factors, exercise, and demographic factors on LVM were determined with multivariate linear regression.

Results:  LVM rose during adolescence and declined in adulthood. LVM and LVMBSA were higher in males both in adults (LVM: 188 ± 22 g versus 139 ± 21 g, P<0·001; LVMBSA: 94 ± 11 g m−2 versus 80 ± 11 g m−2, P<0·001) and in adolescents when adjusted for BSA (LVM: 128 ± 29 g versus 107 ± 20 g, P = 0·063; LVMBSA: 82 ± 8 g m−2 versus 71 ± 10 g m−2, P = 0·025). In adults, systolic blood pressure (SBP) and self‐reported physical activity increased while meridional and circumferential wall stress were constant with age. Multivariate regression analysis revealed age, gender, and BSA as the major determinants of LVM (global R2 = 0·69).

Conclusions:  Normal LVM shows variation over a broad age range in both genders with a rise in adolescence and subsequent decline with increasing age in adulthood despite an increase in SBP and physical activity. BSA, age, and gender were found to be major contributors to the variation in LVM in healthy adults, while haemodynamic factors, exercise, and wall stress were not.
Cardiorespiratory effects of warm water immersion in elderly patients with chronic heart failure
Authors: Cider Åsa , Sunnerhagen Katharina Stibrant , Schaufelberger Maria , Andersson Bert
Published: October 2005

Background: Hydrotherapy might be included in the rehabilitation of patients with chronic heart failure (CHF), but little is known about the acute cardiorespiratory reaction in warm water. The aim of this study was to assess the acute cardiorespiratory effect of immersion in warm water, in a clinical setting, in elderly patients with CHF compared with healthy age and sex matched persons.

Methods: Twelve patients (three females) with CHF, NYHA II–III, age 64 ± 6 years, and 12 healthy subjects were studied. Cardiorespiratory changes, on land and in a temperature‐controlled swimming pool (33–34°C) were assessed during rest and exercise, in a sitting position, using continuous gas analyses.

Results: There were no significant differences, land versus water, in carbon dioxide production, total ventilation, respiratory frequency, respiratory exchange ratio, heart rate or blood pressure in either of the groups. A significant difference was found in oxygen uptake, at rest, land versus water in patients with CHF in comparison with healthy subjects (−0·2 ± 0·4 versus +0·3 ± 0·6 ml kg−1 min−1,P<0·01). Oxygen kinetics (τ) increased significantly (P = 0·01) in both groups during exercise in water.

Conclusion: Hydrotherapy was well tolerated and the vast majority of the cardiorespiratory responses, during warm water immersion in a clinical setting, are similar in patients with CHF compared with healthy subjects. However, further larger studies, are needed to better understand the physiological reactions during hydrotherapy.
Recording of dynamic arterial compliance changes during hand elevation
Authors: Jagomägi Kersti , Raamat Rein , Talts Jaak , Ragun Ulvi , Länsimies Esko , Jurvelin Jukka
Published: October 2005

Finger arterial compliance has been studied on the beat‐to‐beat basis by using the digital arterial pressure and volume waveforms and performing measurements at zero transmural pressure during arm elevation in 11 volunteers. Continuous non‐invasive finger blood pressure was measured by applying the Finapres monitor and the finger volume pulses were recorded by the UT9201 physiograph by using the photoplethysmographic principle of registration. Estimation of the beat‐to‐beat finger arterial compliance is based on (i) the recorded volume and pressure wave amplitudes (Vpulse and Ppulse) and (ii) on the calculation of the slope of the pressure–volume relationship from the first derivatives dV/dt and dP/dt of the recorded volume and pressure pulses near the point of the maximum slope. The results of the study demonstrate that the applied two methods similarly (correlation coefficient r = 0·97) describe the changes of the beat‐to‐beat compliance during hand elevation test. At the same time the second estimate was 18% higher than the first one (P = 0·003).
Intestinal circulation, oxygenation and metabolism is not affected by oleic acid lung injury
Authors: Claesson Jonas , Lehtipalo Stefan , Bergstrand Ulf , Arnerlöv Conny , Rocksen David , Hultin Magnus , Winsö Ola
Published: October 2005

This study was performed to establish a platform for further studies on effects of ventilatory treatment modalities on the intestines during mechanical ventilation of acute lung injury (ALI). We tested the hypotheses that oleic acid (OA) infusion causes changes in intestinal circulation, oxygenation and metabolism, and that OA is distributed to tissues outside the lung. This was performed as an experimental, prospective and controlled study in an university animal research laboratory. Thirteen juvenile anaesthetized pigs were used in the main study, where seven were given an intravenous infusion of 0·1 ml kg−1 OA and six served as control (surgery only). In a separate study, four animals were given an intravenous infusion of 0·1 ml kg−13H‐labelled OA. We measured systemic and mesenteric (portal venous blood flow, jejunal mucosal perfusion) haemodynamic parameters, mesenteric oxygenation (jejunal tissue oxygen tension) and systemic cytokines (tumour necrosis factor‐α and interleukin‐6). We calculated mesenteric lactate flux and mesenteric oxygen delivery, uptake and extraction ratio. In the animals given 3H‐OA, we measured 3H‐OA in different tissues (lungs, heart, liver, kidney, stomach, jejunum, colon and arterial blood). We found that OA given intravenously is distributed in small amounts to the intestines. This intestinal exposure to OA does not cause intestinal injury when evaluating mesenteric blood flow, metabolism or oxygenation. OA infusion induced a moderate increase in mean pulmonary arterial pressure and a decrease in PaO2/Fraction inspired O2 (P/F) ratio, giving evidence of severe lung injury. Consequently, the OA lung injury model is suitable for studies on intestinal effects of ventilatory treatment modalities during mechanical ventilation of ALI.
UNDERSTANDING SIZE AND THE BOOK‐TO‐MARKET RATIO: AN EMPIRICAL EXPLORATION OF BERK'S CRITIQUE
Authors: Fan Xinting , Liu Ming
Published: October 2005

Because they are scaled by price, the ability of size (i.e., the market capitalization of a firm) and the book‐to‐market equity ratio to determine expected returns may, according to Berk (1995), reflect only a simultaneity bias. The two‐stage least squares approach is used to control for this bias and to investigate the economic meanings of these variables. We discover that size and the book‐to‐market ratio contain distinct and significant components of financial distress, growth options, the momentum effect, liquidity, and firm characteristics. Our findings support Berk in his contention that that size and the book‐to‐market ratio reflect a combination of different economic mechanisms that are misspecified in the expected return process.
VOLATILITY FORECASTS, TRADING VOLUME, AND THE ARCH VERSUS OPTION‐IMPLIED VOLATILITY TRADE‐OFF
Authors: Donaldson R. Glen , Kamstra Mark J.
Published: October 2005

We investigate empirically the role of trading volume (1) in predicting the relative informativeness of volatility forecasts produced by autoregressive conditional heteroskedasticity (ARCH) models versus the volatility forecasts derived from option prices, and (2) in improving volatility forecasts produced by ARCH and option models and combinations of models. Daily and monthly data are explored. We find that if trading volume was low during period t−1 relative to the recent past, ARCH is at least as important as options for forecasting future stock market volatility. Conversely, if volume was high during period t−1 relative to the recent past, option‐implied volatility is much more important than ARCH for forecasting future volatility. Considering relative trading volume as a proxy for changes in the set of information available to investors, our findings reveal an important switching role for trading volume between a volatility forecast that reflects relatively stale information (the historical ARCH estimate) and the option‐implied forward‐looking estimate.
DURATION, DEFAULT RISK, AND THE TERM STRUCTURE OF INTEREST RATES
Authors: Xie Yan Alice , Liu Sheen , Wu Chunchi
Published: October 2005

We examine the interactive effect of default and interest rate risk on duration of defaultable bonds. We show that duration for defaultable bonds can be longer or shorter than default‐free bonds depending on the relation between default intensity and interest rates. Empirical evidence indicates that in most cases duration for defaultable bonds is much shorter than for their default‐free counterparts because of the negative relation between default risk and interest rates. Results suggest that the duration measure must be adjusted for the effects of default risk and stochastic interest rates to achieve an effective bond portfolio immunization.
EVIDENCE ON THE MARKET FOR PROFESSIONAL DIRECTORS
Authors: Keys Phyllis Y. , Li Joanne
Published: October 2005

Using the temporary increase in the supply of directors associated with successful tender offers, we examine characteristics of directors who are valuable in the market for board seats. We find that after a takeover, professional directors are three times more likely to receive new appointments than other types of directors released from their respective boards. We find that the proportion of professional directors in above‐average performing targets is significantly greater than that in underperforming targets. Our results indicate that professional directors generally have valuable general human capital that more than offsets the costs of multiple directorships.
INVESTOR OVEROPTIMISM AND PRIVATE EQUITY PLACEMENTS
Authors: Marciukaityte Dalia , Szewczyk Samuel H. , Varma Raj
Published: October 2005

We reexamine investor tendency to overweight recent experiences when predicting future performance of firms by examining a sample of firms making private equity placements. Our findings are consistent with the projection argument that investors use the recent experiences of other firms to predict the success of placing firms. Specifically, we find that the placements preceded by a larger number of recently very successful firms are associated with the significantly more favorable market reaction to the placement announcement and significantly poorer post‐placement stock price performance.
MATCHING FINANCIAL AND REAL INVESTMENT OPTIONS: EVIDENCE FROM WARRANT CALLS
Authors: Garcia‐Feijóo Luis , Howe John S.
Published: October 2005

We provide new evidence on the sequential financing explanation for the use of warrants. Consistent with sequential financing, capital spending starts increasing in the year of the call and peaks three years after the call. In addition, both equity and debt financing increase significantly in the year of the call and remain at high levels. Warrant contract features—the exercise price and the presence or absence of a price condition for callable warrants—are also consistent with the sequential financing hypothesis.
Regeneration of Native Trees in the Presence of Invasive Saltcedar in the Colorado River Delta, Mexico
Authors: NAGLER PAMELA L. , HINOJOSA‐HUERTA OSVEL , GLENN EDWARD P. , GARCIA‐HERNANDEZ JAQUELINE , ROMO REGGIE , CURTIS CHARLES , HUETE ALFREDO R. , NELSON STEPHEN G.
Published: October 2005

Abstract:  Many riparian zones in the Sonoran Desert have been altered by elimination of the normal flood regime; such changes to the flow regime have contributed to the spread of saltcedar (Tamarix ramosissma Ledeb.), an exotic, salt‐tolerant shrub. It has been proposed that reestablishment of a natural flow regime on these rivers might permit passive restoration of native trees, without the need for aggressive saltcedar clearing programs. We tested this proposition in the Colorado River delta in Mexico, which has received a series of large‐volume water releases from U.S. dams over the past 20 years. We mapped the vegetation of the delta riparian corridor through ground and aerial surveys (1999–2002) and satellite imagery (1992–2002) and related vegetation changes to river flood flows and fire events. Although saltcedar is still the dominant plant in the delta, native cottonwood ( Populus fremontii S. Wats.) and willow (Salix gooddingii C. Ball) trees have regenerated multiple times because of frequent flood releases from U.S. dams since 1981. Tree populations are young and dynamic (ages 5–10 years). The primary cause of tree mortality between floods is fire. Biomass in the floodplain, as measured by the normalized difference vegetation index on satellite images, responds positively even to low‐volume (but long‐duration) flood events. Our results support the hypothesis that restoration of a pulse flood regime will regenerate native riparian vegetation despite the presence of a dominant invasive species, but fire management will be necessary to allow mature tree stands to develop.
Predicting Regional Patterns of Similarity in Species Composition for Conservation Planning
Authors: STEINITZ OFER , HELLER JOSEPH , TSOAR ASAF , ROTEM DOTAN , KADMON RONEN
Published: October 2005

Abstract:  In a review of recent challenges in conservation planning, Ferrier (2002) proposed the incorporation of models of similarity in species composition as a means for prioritizing areas for biodiversity conservation. A key assumption of this approach is that estimates of compositional similarity derived from models of similarity in species composition can be used as effective surrogates for real similarity data. We used data on snail distribution in Israel to test this assumption. We used two types of models to analyze patterns of similarity in species composition: one based on presence/absence data and the second based on abundance data. Both models accounted for large amounts of the observed variation in compositional similarity. Variation‐partitioning analysis indicated that a considerable amount of the variation in compositional similarity could be separated into “pure” geographical versus “pure” environmental components, indicating that reserve selection procedures should take into account spatial considerations in determining priorities for conservation. The relative effects of geographical versus environmental factors varied between the two types of models, indicating that different indices of similarity should be used if one wishes to represent species composition per se or ecological communities including their relative species abundances. A comparison of distribution patterns of land snails and land birds in a subset of the study sites revealed a high degree of congruence in compositional similarity between the two groups. Moreover, compositional similarity in snails was a better predictor of compositional similarity in birds compared with all environmental and geographical distances taken together. Models calibrated based on data collected in small plots explained a considerable amount of the variation observed at larger scales, suggesting that sampling efforts required for conservation planning might be lower (and thus, more feasible) than assumed previously. Models of similarity in species composition may serve as an important tool for conservation planning.
Forest Roads as Partial Barriers to Terrestrial Salamander Movement
Authors: MARSH DAVID M. , MILAM GRAHAM S. , GORHAM NICHOLAS P. , BECKMAN NOELLE G.
Published: October 2005

Abstract:  Roads can fragment animal populations by disrupting movement among formerly continuous habitats. Although models have demonstrated that disrupted movement can contribute to long‐term extinction, there are few empirical data on the effects of roads on animal movement. We used displacement and homing experiments to determine whether forest roads are barriers to the movement of terrestrial salamanders. We displaced 1471 red‐backed salamanders (Plethodon cinereus) across five forest roads and compared return rates to those of salamanders displaced equal distances toward the forest interior. Roads significantly reduced the return rate of salamanders, with a mean reduction of 51%. Steep roadside verges further reduced return rates, particularly for salamanders moving downhill across verges. The permeability of roads to salamander movement did not appear to be related to road surface type. Gravel roads had both the highest and lowest observed permeability with the two paved roads intermediate between these. We conclude that narrow forest roads are partial barriers to salamander movement and that steep roadside verges may exacerbate these effects.
Predicting Plant Extinction Based on Species‐Area Curves in Prairie Fragments with High Beta Richness
Authors: WILSEY BRIAN J. , MARTIN LEANNE M. , POLLEY H. WAYNE
Published: October 2005

Abstract: Species‐area relationships and island biogeography theory are commonly used to predict how species richness will decline with fragmentation. There are a variety of largely untested assumptions in these approaches, including the assumptions that populations are distributed uniformly before fragmentation, and that local extinctions are due to effects of small population sizes. If populations are not distributed uniformly, then populations can be abundant locally but rare globally. This would cause extinction rates to be smaller than predicted. We tested extinction theory by developing estimates of the number of plant species that should be present in small tallgrass prairie fragments and then testing the uniformity assumption by partitioning species richness into α (within site) and β (among site) components in Iowa prairies. Many more native prairie plant species were present in surveys of prairie fragments (491) than was predicted based on theory (27–207). A large proportion (75%) of the total species richness was β richness. We suggest that the high proportion of β richness was responsible for the shallow species‐area slopes and the lower than expected number of species losses and that a better understanding of what determines β diversity will improve predictions of fragmentation effects on richness of plants. We also suggest that plants in prairie remnants may be best conserved by protecting different prairie types rather than by protecting a few large areas containing a single prairie type.
One Hundred Fifty Years of Change in Forest Bird Breeding Habitat: Estimates of Species Distributions
Authors: SCHULTE LISA A. , PIDGEON ANNA M. , MLADENOFF DAVID J.
Published: October 2005

Abstract: Evaluating bird population trends requires baseline data. In North America the earliest population data available are those from the late 1960s. Forest conditions in the northern Great Lake states (U.S.A.), however, have undergone succession since the region was originally cut over around the turn of the twentieth century, and it is expected that bird populations have undergone concomitant change. We propose pre‐Euro‐American settlement as an alternative baseline for assessing changes in bird populations. We evaluated the amount, quality, and distribution of breeding bird habitat during the mid‐1800s and early 1990s for three forest birds: the Pine Warbler (Dendroica pinus), Blackburnian Warbler (D. fusca), and Black‐throated Green Warbler (D. virens). We constructed models of bird and habitat relationships based on literature review and regional data sets of bird abundance and applied these models to widely available vegetation data. Original public‐land survey records represented historical habitat conditions, and a combination of forest inventory and national land‐cover data represented current conditions. We assessed model robustness by comparing current habitat distribution to actual breeding bird locations from the Wisconsin Breeding Bird Atlas. The model showed little change in the overall amount of Pine Warbler habitat, whereas both the Blackburnian Warber and the Black‐throated Green Warbler have experienced substantial habitat losses. For the species we examined, habitat quality has degraded since presettlement and the spatial distribution of habitat shifted among ecoregions, with range expansion accompanying forest incursion into previously open habitats or the replacement of native forests with pine plantations. Sources of habitat loss and degradation include loss of conifers and loss of large trees. Using widely available data sources in a habitat suitability model framework, our method provides a long‐term analysis of change in bird habitat and a presettlement baseline for assessing current conservation priority.
Modeling the Effects of Limiting the Number of Visitors on Failure Rates of Seabird Nests
Authors: BEALE COLIN M. , MONAGHAN P.
Published: October 2005

Abstract:  Most attempts to manage disturbance by visitors to nature reserves concentrate on limiting visitor access in some way, which is often unpopular with both visitors and managers. In a few nature reserves the daily numbers of visitors are limited, an action that need not necessarily reduce the total number of visitors. As a test of the assumptions that underlie this management practice, we examined the relationship between daily visitor numbers and daily failure rates of nests in two species of seabirds. Daily failure rates for Black‐legged Kittiwakes (Rissa tridactyla) were weakly correlated with daily visitor numbers but indicated that capping daily visitor numbers slightly reduced overall breeding success. This was not the case for Common Murres (Uria aalge), where failure rate declined seasonally but was not significantly correlated with visitor numbers. For some species, it appears that capping daily visitor numbers may have small conservation costs.
Effects of Urbanization on the Distribution and Abundance of Amphibians and Invasive Species in Southern California Streams
Authors: RILEY SETH P. D. , BUSTEED GARY T. , KATS LEE B. , VANDERGON THOMAS L. , LEE LENA F. S. , DAGIT ROSI G. , KERBY JACOB L. , FISHER ROBERT N. , SAUVAJOT RAYMOND M.
Published: October 2005

Abstract:  Urbanization negatively affects natural ecosystems in many ways, and aquatic systems in particular. Urbanization is also cited as one of the potential contributors to recent dramatic declines in amphibian populations. From 2000 to 2002 we determined the distribution and abundance of native amphibians and exotic predators and characterized stream habitat and invertebrate communities in 35 streams in an urbanized landscape north of Los Angeles (U.S.A.). We measured watershed development as the percentage of area within each watershed occupied by urban land uses. Streams in more developed watersheds often had exotic crayfish (Procambarus clarkii) and fish, and had fewer native species such as California newts (Taricha torosa) and California treefrogs (Hyla cadaverina). These effects seemed particularly evident above 8% development, a result coincident with other urban stream studies that show negative impacts beginning at 10–15% urbanization. For Pacific treefrogs (H. regilla), the most widespread native amphibian, abundance was lower in the presence of exotic crayfish, although direct urbanization effects were not found. Benthic macroinvertebrate communities were also less diverse in urban streams, especially for sensitive species. Faunal community changes in urban streams may be related to changes in physical stream habitat, such as fewer pool and more run habitats and increased water depth and flow, leading to more permanent streams. Variation in stream permanence was particularly evident in 2002, a dry year when many natural streams were dry but urban streams were relatively unchanged. Urbanization has significantly altered stream habitat in this region and may enhance invasion by exotic species and negatively affect diversity and abundance of native amphibians.
Mortality and Adverse Health Events in Newly Admitted Nursing Home Residents with and without Dementia
Authors: Magaziner Jay , Zimmerman Sheryl , Gruber‐Baldini Ann L. , Van Doorn Carol , Hebel J. Richard , German Pearl , Burton Lynda , Taler George , May Conrad , Quinn Charlene C. , Port Cynthia L. , Baumgarten Mona ,   for the Epidemiology of Dementia in Nursing Homes Research Group
Published: October 2005

Objectives: To evaluate the association between dementia and mortality, adverse health events, and discharge disposition of newly admitted nursing home residents. It was hypothesized that residents with dementia would die at a higher rate and develop more adverse health events (e.g., infections, fevers, pressure ulcers, falls) than residents without dementia because of communication and self‐care difficulties.

Design: An expert clinician panel diagnosed an admission cohort from a stratified random sample of 59 Maryland nursing homes, between 1992 and 1995. The cohort was followed for up to 2 years or until discharge.

Setting: Fifty‐nine Maryland nursing homes.

Participants: Two thousand one hundred fifty‐three newly admitted residents aged 65 and older not having resided in a nursing home for 8 or more days in the previous year.

Measurements: Mortality, infection, fever, pressure ulcers, fractures, and discharge home.

Results: Residents with dementia had significantly lower overall rates of infection (relative risk (RR)=0.77, 95% confidence interval (CI)=0.70–0.85) and mortality (RR=0.61, 95% CI=0.53–0.71) than those without dementia, whereas rates of fever, pressure ulcers, and fractures were similar for the two groups. These results persisted when rates were adjusted for demographic characteristics, comorbid conditions, and functional status. During the first 90 days of the nursing home stay, residents with dementia had significantly lower rates of mortality if not admitted for rehabilitative care under a Medicare qualifying stay (RR=0.25, 95% CI=0.14–0.45), were less often discharged home (RR=0.33, 95% CI=0.28–0.38), and tended to have lower fever rates (RR=0.78, 95% CI=0.63–0.96) than residents without dementia.

Conclusion: Newly admitted nursing home residents with dementia have a profile of health events that is distinct from that of residents without dementia, indicating that the two groups have different long‐term care needs. Results suggest that further investigation of whether residents with dementia can be well managed in alternative residential settings would be valuable.
No Old Man Ever Forgot Where He Buried His Treasure: Concepts of Cognitive Impairment in Old Age Circa 1700
Authors: Schäfer Daniel
Published: October 2005

Cognitive impairment in old age is one of the most important topics in modern geriatrics. This article discusses the historical dimensions of this phenomenon. To this end, a number of primary sources ranging from antiquity to the modern era are evaluated. Although a physiology and pathology of old age were conceptualized in Greco‐Roman times, cognitive impairment in old age remained a marginal issue until the 17th century. Alternatively, after 1500, medicine boasted detailed theories on the physiology and pathology of old age. There are several possible explanations for this unusual situation. Underlying conflict between idealistic and materialistic views of man played a decisive role, for these concepts differed considerably regarding the intellectual and mental functioning of the soul as well as the effects of the passage of time. After Cartesianism and Iatromechanism had pushed these traditional boundaries back, the problem of cognitive impairment in old age was increasingly regarded as a physical illness and began to receive more attention. Just as its philosophical and theological context shaped early modern medicine, contemporary nonmedical disciplines such as genetics, (neuro‐)biology, and the information sciences influence modern research.