bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluating Training By Four Economic Indices
Authors: Rosentreter Gary
Published: March 2007

The purpose of this study was to demonstrate the viability of selected economic indices as criteria for evaluation of a manufacturing firm's adult education pro gram. The adult education program studied was designed to increase managers' facilitative communication skills for goal setting with subordinates. To ascertain the effectiveness of the program, four measures of results were compared before and six months after the training program: (1) turnover of subordinates, (2) in cidence of subordinates' tardiness, (3) the manager's performance appraisal ratings, and (4) incidence of subordinates' formal grievances. The results permit ted two conclusions: (1) the program was effective in bringing about change with regard to employee turnover; (2) the program did not result in significant change with regard to the three other variables. However, the study lends support to the idea that training outcomes can be measured in terms of selected economic in dices.
A Critical Theory of Adult Learning and Education
Authors: Mezirow Jack
Published: March 2007

Interpreting the ideas of Jurgen Habermas, the nature of three generic domains of adult learning is posited, each with its own interpretive categories, ways of determining which knowledge claims are warranted, methods of inquiry as well as its own learning goals, learning needs and modes of educational intervention. Perspective transformation is seen as one of the learning domains and the domain most uniquely adult. The nature and etiology of perspective transformation is elaborated with particular focus on the function of reification and of reflectivity. Implications of a critical theory for self-directed learning and adult education are explored. A Charter for Andragogy is suggested.
The Impact of Interests, Power Relationships, and Organizational Structure On Program Planning Practice: A Case Study
Authors: Mills David P. , Cervero Ronald M. , Langone Christine A. , Wilson Arthur L.
Published: March 2007

The central purpose of this study was to show how the personal and organizational interests of adult educators are causally related to the planning of educational programs. A qualitative multi-case study was conducted of six county extension agents and four district program development specialists in the Cooperative Extension System. The study shows how traditionalist interests are embedded in the contextual factors that affect the planning practices of county agents and the ways in which these factors affected the seven programs planned by these agents. Specifically, three categories of structural factors were found to constrain or enable county agents' planning practices: a) organizational structure and culture, b) available resources, and c) power relationships. These factors affected the programs that county agents constructed through their planning practices in terms of the needs addressed and the planning process employed.
Teacher Attitudes on Diversity Affecting Student Socio-Academic Responses: An Ethnographic View
Authors: Delgado-Gaitan Concha
Published: March 2007

An alternative theoretical perspective underlies this ethnographic study on high school students' schooling practices. Teacher attitudes in the classroom were identified and described by the students and parents as qualitatively affecting the students academic performance. Students devise long term strategies to deal with the emotional impact of teachers' disapproving attitudes. Teacher perceptions toward social and ethnic diversity govern teacher/student interaction and the overall classroom curriculum. Family and peer groups are a fundamental part of the socialization process of the students' learning environment and their socio-academic responses to teachers' perception of them. The findings show implications in teacher education as well as community support organizations and parent training programs.
Cross-Cultural Comparability of Temperament among Japanese and American Early- and Late-Adolescents
Authors: Windle Michael , Iwawaki Saburo , Lerner Richard M.
Published: March 2007

The cross-cultural generalizability of temperament, as measured by the Revised Dimensions of Temperament Survey (DOTS-R) (Windle & Lerner, 1986), was investigated by studying metric equivalent relations between samples of Japanese and American early adolescents, and between samples of Japanese and American late adolescents. Similar to findings for the American adolescent samples, nine-and ten-factor models were found to adequately represent the inter-item covariance matrix of the DOTS-R for the Japanese early and late-adolescents, respectively. Metric equivalence between the early-and late-adolescent samples, respectively, was supported via congruence coefficients and restricted (confirmatory), simultaneous group models for each of the separate temperament dimensions. Statistical tests of differences in factor means were conducted and indicated that American early-and late-adolescents rated themselves higher in approach behavior, mood quality (positive affect), and task orientation. The Japanese early adolescents rated themselves higher with respect to features of behavioral rhythmicity. No statistically significant differences were found for almost one-half of the factor mean comparisons. Proposals for future cross-cultural research in adolescent temperament which move beyond measurement equivalence issues were suggested to address issues of similarities and differences between cultural groups with respect to causal linkages. In addition, we suggest the use of additional methods of measurement conjointly with the DOTS-R in order to triangulate on salient temperament constructs.
Adolescents' Honesty in a Survey of Sexual Behavior
Authors: Newcomer Susan , Udry J. Richard , Hill Chapel
Published: March 2007

Adolescents' reports of whether they told the truth about having had intercourse when answering a two years prior survey of sexual behavior are used to examine the correlates of such behavior. Seven percent of the young people say they did not tell the truth at Time 1. Another substan tial proportion seem to be unclear about what they said, and, perhaps, about the timing of their first intercourse. Implications of these findings for survey researchers are discussed.
Depressive Symptoms in Adolescents as a Function of Perceived Parental Behavior
Authors: Baron Pierre , MacGillivray Richard G.
Published: March 2007

The present study aimed at examining the relation between perceived parental behavior and depressive symptoms in adolescents. One hundred forty-four adolescents, ranging in age from 13 to 18 years, were involved in the study. They all came from a high school of the Western Quebec Regional School Board. Subjects completed the Children s Report of Parental Behavior Inventory (revised form) and the Beck Depression Inventory. Father's rejection and mother's psychological control were found to be the two most powerful predictors of adolescents' depressive symptoms. Results are discussed in light of the literature on adolescent depression.
Academic and Intellectual Functioning of Adolescents with Closed Head Injury
Authors: Slater Elisa J. , Kohr Melinda A.
Published: March 2007

Adolescents with head injury often return to school and experience difficulty in their academic pursuits. A cademic and intellectual functioning of adolescents with closed head injury (CHI) was assessed immediately and six months posttrauma. Data on school and health history were also collected. T-tests and chi-square analyses were used to determine differences between the CHI group (n = 33) and their matched controls (n = 32). Results indicated that both initially and at six months postinjury the CHI group was functioning lower academically and intellectually in comparison to their peers. No differences were found in their developmental or psychiatric history. However, based upon data from a subset of the sample, the CHI group had lower English grades and grade point averages the year prior to their injury. Three areas for further research are discussed.
Long-Term Outcomes of Adolescent Sibling Bereavement
Authors: Davies Betty
Published: March 2007

The experience of sibling bereavement is relatively unexamined in the literature; the long-term effects of such an experience have received even less attention. In this study, grounded theory techniques for the analysis of qualitative data were used to analyze a series of intensive, semistructured interviews with 12 adults who, in their early adolescence, lost a sibling. Long-term outcomes included psychological growth, a sense of feeling different, and withdrawal from peers. The study presents a theoretic scheme relating these outcomes. The sense of personal growth and maturity arouses feelings of being different from peers, and may result in an intolerance of the developmentally appropriate behaviors demonstrated by peers. Some siblings respond to these feelings by withdrawing from their peers at a time when peer relationships are critical to completing developmental tasks. For such siblings, feelings of sadness and loneliness become long-term.
The Relation of Attachments and Supports to Adolescent Well-Being and School Adjustment
Authors: Cotterell John L.
Published: March 2007

This study examined the relationship between adolescents 'adjustment and their supportive relations with significant others. It linked the Bowlby concept of social attachment with that of social support (derived from social network theory) in describing the exchange content of adolescents' interactions with parents, peer-friends, and adult nonkin. Within each of these three support systems, only moderate relationships were found between adolescents' number of supports and the strength of attachments to members of the respective support systems. Fewer relationships were found between supports and adjustment than between attachments and adjustment. For both sexes, the strength of attachments to parents and to teachers was associated with young people's positive feelings about themselves. Network ties providing informational support (encouragement, guidance, and advice) were related to girls'and boys'academic outcomes in different ways: among girls, support from parents and adult nonkin was related to academic self-concept, whereas among boys, support from friends was negatively related to self-concept and educational plans.
Attachment and Perceived Social Support in Late Adolescence
Authors: Blain Michelle D. , Thompson Janny M. , Whiffen Valerie E.
Published: March 2007

Research has shown that self-perceptions are associated with perceived social support. Attachment theory suggests that perceptions of social support are afunction of two types of internal working models: model of self (beliefs about self-worth) and model of others (beliefs about the availability and responsiveness of others). This study investigated the relationship between models of self and others and perceived social support. Undergraduates (143 females, 73 males) completed questionnaires assessing attachment to parents andfriends and perceived social support. Analyses confirmed that individuals reporting positive models of both self and others (secure attachment) also reported the highest levels of perceived social supportfrom parents andfriends and attachment tofriends. A negative model of self or other (insecure attachment) had a negative impact on perceived social support and attachment to friends. A negative model of self had a particularly negative impact on attachment to friends for males.
Adolescents' Relationships with Father, Mother, and Same-Gender Friend
Authors: Mayseless Ofra , Wiseman Hadas , Hai Ilan
Published: March 2007

Examined in this study were age differences in autonomy and relatedness in adolescents' relationships with parents as well as the association between adolescents'relationships with mother and with father and with a same-gender friend. The Relationship with Father/Mother Questionnaire (RFMQ) and the Sharabany Intimacy Scale were administered to 205 Israeli adolescents (105 males and 100females)from two age groups: 9th grade (age X = 14.5) and 12th grade (age X = 175). Older adolescents reported more autonomy in their relationships with parents than did younger adolescents, but no age differences were found in closeness and warmth. On the basis of a cluster analysis of the RFMQ, it was found that adolescents who reported an Ideal profile of relationships with their parents and those reporting a Cold and Controlling profile of relationships with them were alike in having higher intimacy with their best fiend compared with other groups of adolescents.
Prospective Risk Factors and Treatment Outcomes among Adolescents in DATOS-A
Authors: Galaif Elisha R. , Hser Yih-Ing , Grella Christine E. , Joshi Vandana
Published: March 2007

The relationships between risk factors and outcomes in adolescents participating in the Drug Abuse Treatment Outcome Studies for Adolescents (DATOS-A) were examined. The study included 292 admissions to nine outpatient drug-free (ODF) and 418 admissions to eight residential (RES) programs. Assessments were administered at intake into treatment and 12 months following discharge. For ODF participants, (a) severity of drug use predicted less retention in treatment, and (b) family drug involvement predicted more alcohol use after treatment. For RES participants, (a) family drug involvement and criminal involvement predicted less treatment retention, and (b) conduct disorder predicted more marijuana use at follow-up. The findings underscore the need for intervention strategies that address the intrapsychic and interpersonal functioning of drug-abusing adolescents to improve their behavioral outcomes.
A Brief Report
Authors: Davis Larry E. , Johnson Sharon , Cribbs Julie Miller , Saunders Jeanne
Published: March 2007

The goal of the study was to assess positive factors that contribute to African American students’intentions to stay in school. Two hundred and thirty-one African American students participated in this study. Using the theory of planned behavior (TPB) as a conceptual model, surveys measured student attitudes toward school-year completion, social support for completing the academic year, and their perceptions of personal control over school completion. The contributions of self-esteemand racial self-esteemwere also examined for their influence on academic strivings. The TPB was a better predictor of intentions to complete the school year than student grade point averages (GPAs). Self-esteemadded only slightly to the variance explained in predicting intentions to complete the school year, but neither self-esteemnor racial self-esteemwas a significant predictor of GPAs.
A Congregation of One
Authors: Arnett Jeffrey Jensen , Jensen Lene Arnett
Published: March 2007

Religious beliefs and practices were examined among 140 emerging adults aged 21 to 28, using quantitative and qualitative methods. There was great diversity in the importance they ascribed to religion, in their attendance at religious services, and in the content of their religious beliefs. Overall, their beliefs fell into four roughly even categories—agnostic/atheist, deist, liberal Christian, and conservative Christian—but there was also considerable diversity within each category. In combination, the quantitative and qualitative results showed that the participants’beliefs were highly individualized, that there was little relationship between childhood religious socialization and current religious attendance or beliefs, and that the participants were often skeptical of religious institutions. The results reflect the individualism of American society as well as the focus in emerging adulthood on forming one’s own beliefs.
Early Environmental Support and Elementary School Adjustment as Predictors of School Adjustment in Middle Adolescence
Authors: Carlson Elizabeth A. , Sroufe L. Alan , Collins W. Andrew , Jimerson Shane , Weinfield Nancy , Hennighausen Katherine , Egeland Byron , Hyson Daniel M. , Anderson Fiona , Meyer Stephanie E.
Published: March 2007

Longitudinal data from a high-risk sample (N = 173, male: n = 93, female: n = 80) were used to examine socioemotional antecedents of school adjustment in adolescence. Parental problem-solving support in early childhood and early adolescence and measures of peer competence, externalizing behavior, and emotional health/self-esteem in early middle childhood were examined both independently and in relation to academic achievement in early middle childhood as predictors of high school adjustment. For this sample, early and later parental problem-solving support alone accounted for 13% of the variance in high school adjustment. Early and later parental problem-solving support and measures of peer competence, externalizing behavior, and emotional health/self-esteem in early middle childhood accounted for 32% of the total variance in high school adjustment with or without early academic achievement taken into account. In regression analyses controlling for socioeconomic status and prior achievement, middle childhood socioemotional variables significantly predicted high school adjustment. Modest differences in results for boys and girls were obtained.
Further Evidence that the Circadian Clock in Drosophila is a Population of Coupled Ultradian Oscillators
Authors: Dowse H.B. , Ringo J.M.
Published: March 2007

We hypothesize that ultradian oscillators are coupled to yield a composite circadian clock in Drosophila. In such a system, period would be a function of the tightness of coupling of these oscillators, increasing as coupling loosens. Ultradian oscillations would become appar ent under weak coupling or in the absence of coupling. A new technique for calculating signal- to-noise ratio (SNR) for biological rhythms to characterize their precision has yielded support for this hypothesis. SNR of rhythms of the allelic series of mutations at the period ( per) locus of Drosophila melanogaster were compared. per0 was the noisiest, grading through perL, per+ , and pers, the least noisy. SNR decreases significantly with increasing period in pers, per+, and perL; pero typically has multiple ultradian oscillations and the lowest SNR. At least 70% of perL individuals also exhibit ultradian periodicities.
Differential Effects of Pinealectomy on Circadian Rhythms of Feeding and Perch Hopping in the European Starling
Authors: Gwinner Eberhard , Subbaraj Ramanujam , Bluhm Cynthia K. , Gerkema Menno
Published: March 2007

To study the effects of pinealectomy on the circadian rhythms of locomotor activity and feeding, European starlings (Sturnus vulgaris) were held in constant light (0.2 lux and 200 lux) and under constant temperature conditions. Locomotor activity was measured by means of perches with microswitches mounted underneath, and feeding with an infrared photocell system at the feeder. Pinealectomy consistently led to disturbances in perch-hopping rhythms and often to a complete loss of rhythmicity as revealed by periodogram analysis. In some birds, perch-hopping rhythms recovered following a period of initial arrhythmicity. When a perch- hopping rhythm was present, its period was usually shorter than it had been before pinealec tomy. In contrast to its effects on perch hopping, pinealectomy had no effect on the persistence of feeding rhythmicity, although its period, like that of the hopping rhythm, decreased after this operation. These results support the hypothesis derived from previous studies that the circadian organization of feeding is different from that of perch hopping. Different circadian pacemakers may be involved, but other models may possibly explain the data just as well.
Are Protein Synthesis Inhibition and Phase Shifting of the Circadian Clock in Gonyaulax Correlated?
Authors: Olesiak Walter , Ungar Anne , Johnson Carl Hirschie , Hastings J. Woodland
Published: March 2007

We describe a method whereby the effect of protein synthesis inhibitors upon protein synthesis in Gonyaulax cultures may be reliably measured. Using this method, we found that protein synthesis inhibition and clock resetting were correlated, but that the correlation was not as close as has been reported in other systems. The effect of the inhibitors anisomycin and cycloheximide upon phase shifting of the circadian clock was a function of the illumination and temperature conditions to which the cells were subjected, but these factors did not appear to influence the inhibition of protein synthesis by these drugs. Cellular protein synthesis did not recover immediately from the inhibitors' effects; depending upon the previous concentration of the inhibitor, translational recovery from the drugs may require hours. This observation has important implications for the analysis of any phase response curve when the stimulus is a chemical.
Axon-Sparing Lesions of the Hypothalamic Paraventricular Nucleus Abolish Gonadal Responses to Photoperiod in Male Syrian Hamsters
Authors: Brown Michael H. , Badura Lori L. , Nunez Antonio A.
Published: March 2007

Intrahypothalamic injections of the excitotoxin N-methyl-D,L-aspartic acid (NMA) that destroyed the parvocellular regions of the paraventricular nucleus (PVN) prevented go nadal regression in male hamsters (Mesocricetus auratus) kept in short days (LD 6:18). After 17 weeks in short days, these NMA-injected animals had large, functional gonads and dis played all components of male sexual behavior. These findings confirm that neurons of the PVN are part of the pathway that mediates photoperiodism in hamsters.
The Effects of Intraventricular Carbachol Injections on the Free-Running Activity Rhythm of the Hamster
Authors: Meijer Johanna H. , van der Zee E. , Dietz M.
Published: March 2007

The effects of light on the circadian pacemaker in the suprachiasmatic nucleus (SCN) are mediated by the retinohypothalamic tract (RHT) and by the retinogeniculosupra chiasmatic tract (RGST). The neurotransmitter of the RGST is neuropeptide Y. The RHT may contain glutamate and aspartate. Recent evidence indicates that acetylcholine could also be involved in phase shifting by light. We determined that intraventricular injections with an acetylcholine agonist, carbachol, induces phase advances during the subjective day and phase delays during the early subjective night. No differences were observed between phase shifts induced in constant darkness and those induced in continuous light. A dose-response curve for carbachol was described at circadian time 6 (CT6). Injections at CT14 with various dosages of carbachol indicated the same dose dependency for this circadian time. Finally, carbachol injections in split animals resulted in similar responses of the two components of the split activity rhythm.
Nonphotic Enhancement of Adjustment to New Light—Dark Cycles: Masking Interpretation Discounted
Authors: Mrosovsky N.
Published: March 2007

The adjustment of hamsters to advanced light-dark (LD) cycles can be greatly accelerated by scheduling a single 3-hr bout of extra activity in a novel running wheel, starting about 7 hr before the time when the animals become active in the preceding LD cycle. The present experiments were designed to provide stronger evidence that this effect depends on a shift in the pacemaker rather than on masking. It was shown that when hamsters were put into continuous darkness (DD) 1 day after the exercise-accelerated phase shift, their free-running rhythms took off from a time nearer to the onset of darkness in the new LD cycle than in the preceding LD cycle. An incidental finding was that in DD the free-running period of the hamsters with the accelerated phase shifts was longer than that of the control animals. Further evidence that the 3-hr exercise pulse had produced a greater phase advance than that occur ring in undisturbed control animals was obtained by giving a light pulse at the same clock time to all animals after they had been in DD for 8 days. The animals that had previously exercised for the additional 3-hr phase-advanced in response to the light pulse, while the undisturbed control animals phase-delayed.
The Stability of the Circadian Rhythm of Green Finches (Carduelis chloris) under the Influence of a Weak Electrical Field
Authors: Lintzen Thomas , Boese Günter , Müller Michael , Eichmeier Joseph , Ruhenstroth-Bauer Gerhard
Published: March 2007

Free-running activity rhythms of nine green finches ( Carduelis chloris) were stud ied under the influence of a 10-Hz square-wave electrical field. With a field strength of |E| = 2.5 V/m in the empty cage, the population had a mean period of 23.64 ± 0.77 hr. In the same experiment, but without the electrical field, the period was 23.66 ± 0.80 hr. These results are in contradiction to Wever's description of a field-induced shortening of the period. A series of experiments with 10-Hz pulses of the same square-wave form, yet with various field strengths (8.7 and 65.2 V/m), also gave no effects.
Phase Determination of the Circadian Rhythm of Conidiation in Heterocaryons between two out-of-Phase Mycelia in Neurospora crassa
Authors: Nakashima H. , Hastings J.W.
Published: March 2007

Neurospora grows vegetatively as a syncytium in which multiple nuclei exist within a connected cytoplasm. Because of the ability of separate and distinct mycelia to fuse, the possibility exists of generating heterocaryotic cultures in which the nuclei and cytoplasms of two different strains are comingled into the same syncytium. We have used such hetero caryons, in which the component parts differed with respect to their circadian clock phase, to examine whether or not clock-dominant phases exist in the circadian cycle. To this end, the phase subsequent to the formation of heterocaryons by pairs of mycelial discs that are initially at different circadian phases was examined in Neurospora crassa. The resulting phase was an average of the parent phases in many cases, but was sometimes observed to correspond more closely to just one of the original parental phases. In these cases, we did not observe any dominant phases in the circadian cycle; the phase of a particular parent disc was more dominant in the heterocaryon when the proportion of the nuclei from that parent was greater in the heterocaryon. In some instances, which occurred mostly when the difference in phase of the parental discs was large, the resultant phase could not be related in a simple way to the parental phases. An interpretation based on a limit cycle model of the circadian oscillation is possible.
Light and Norepinephrine Similarly Prevent Damping of the Melatonin Rhythm in Cultured Chick Pineal Cells: Regulation of Coupling between the Pacemaker and Overt Rhythms?
Authors: Zatz Martin
Published: March 2007

The circadian rhythm of melatonin output displayed by chick pineal cells in static culture damps rapidly in constant red light (RR). This can be seen in the first cycle following a switch from a cycle of 12 hr white light (L) and 12 hr red light (R) to RR. Melatonin output is higher during the "day" in R than it is in L, but higher that next night (in R) after daytime L than after daytime R. This effect might be due entirely to the entraining effect of L. Alternatively, the higher nocturnal output after daytime L could be related to the acute suppression caused by L; it might be a "rebound" phenomenon. These alternative hypotheses differ in their predictions for the effects of norepinephrine (NE) and pertussis toxin (PT). Previous results dissociated the acute and entraining effects of L: PT blocks the acute effect but not the entraining effect of L. NE mimics the acute effect of L (and is blocked by PT), but not the entraining effect. If L prevents damping entirely by entrainment, then NE should not mimic and PT should not block this same-cycle effect of daytime L on nocturnal melatonin output. However, the present research found that NE did mimic and PT did block this effect, indicating that the ability of L to prevent damping is mediated by a same-cycle "rebound" following L's acute inhibition of melatonin production. Furthermore, NE enhanced the "rebound" effect of daytime L, and cycles substituting NE for L were effective in driving the melatonin rhythm. Lowering extracellular potassium did not induce a "rebound," and adding exogenous melatonin did not prevent one. The difference between nocturnal melatonin synthesis after daytime R and that after daytime L or NE implies regulation of coupling between the output of the circadian pacemaker and melatonin production. These results also suggest a role for NE in regulating and maintaining the expression of the melatonin rhythm.
Control of Annual Endocrine Rhythms in the Edible Dormouse: Nonprimary Effect of Photoperiod
Authors: Jallageas Monique , Mas Nicole , Nouguier-Soulé Janine
Published: March 2007

We investigated the extent to which photoperiodic fluctuations synchronize annual thyroid and gonadal rhythmicity in edible dormice. The effects of different daylength manipulations (LD 4:20, LD 6:18, LD 18:6, LD 20:4) were examined during the two critical ascending and regressive phases of the annual plasma testosterone and thyroxine cycles that correspond to naturally increasing or decreasing photoperiod variations. The data failed to demonstrate any essential photoperiodic contribution to control systems that generate these two annual biological rhythms in dormice.
The Topology of Phase Response Curves Induced by Single and Paired Stimuli in Spontaneously Oscillating Chick Heart Cell Aggregates
Authors: Zeng Wanzhen  , Glass Leon , Shrier Alvin
Published: March 2007

The topological properties of the phase resetting of biological oscillators by an isolated stimulus delivered at various phases of the cycle depend on whether the stimulus is "weak" or "strong." When multiple stimuli are delivered to the oscillator, the response to stimulation also depends on the time between the stimuli, and the rate at which the oscillator returns to an underlying limit cycle attractor. If the time between two consecutive "weak" stimuli is sufficiently short, the effects produced by the pair of stimuli may be characteristic of a single "strong" stimulus. These results are demonstrated in a model experimental system, spontaneously beating aggregates of cells derived from embryonic chick heart, and are illustrated by consideration of a simple theoretical model of nonlinear oscillators, the Poincaré oscillator.
Properties of Mutual Coupling between the Two Circadian Pacemakers in the Eyes of the Mollusc Bulla gouldiana
Authors: Page Terry L. , Nalovic Katarina G.
Published: March 2007

We examined, in vitro, the effects of changing the free-running period (τ) of one oscillator on the phase relationship between the circadian rhythms of impulse activity in the optic nerves that are driven by the bilaterally paired ocular pacemakers in Bulla gouldiana. One eye of the coupled pair was treated either with lithium artificial seawater (to lengthen τ) or with low-chloride artificial seawater (to shorten τ). The results suggested that the coupling is relatively weak, since the majority (9 to 16) of eyes were unable to maintain a stable phase relationship when τ differences between the eyes were only about 1 hr. When stable phase differences were achieved, the τ of the coupled system was intermediate between the τ's of the individual oscillators, and the eye with the shorter intrinsic τ would invariably phase-lead the pair. Interestingly, in a few instances, pairs of eyes that had desynchronized by 9.5-10.5 hr resynchronized within a single cycle via a massive phase advance in the rhythm from the phase-lagging eye. The result suggests the existence of a novel phase-shifting mechanism that is part of the mutual coupling pathway. We found evidence that connection of the eye with the cerebral ganglion increases the τ of the ocular pacemaker, suggesting that efferent signals from the central nervous system influence τ. These signals may also modulate the phase-shifting response.
Circadian and Photoperiodic Time Measurement in Male Syrian Hamsters Following Lesions of the Melatonin-Binding Sites of the Paraventricular Thalamus
Authors: Ebling Francis J. P. , Maywood Elizabeth S. , Humby Trevor , Hastings Michael H.
Published: March 2007

Autoradiographic studies using [125I]iodomelatonin in several species, including the Syrian hamster, have revealed that the rostral region of the anterior paraventricular nucleus of the thalamus (aPVT) contains a very high density of binding sites for melatonin. In two studies, small or large bilateral electrolytic lesions of the aPVT were made in adult male hamsters maintained on long days (LD 16:8). The hamsters were then transferred to short days (LD 8:16) to test whether testicular regression could occur in response to a decrease in photoperiod. Serum prolactin concentrations were measured as a second photoperiodic response. All unoperated control hamsters showed the typical short-day photoperiodic response: A decrease in serum luteinizing hormone (LH) and prolactin concentrations and testicular regression all occurred within 6 weeks in short days, followed by the development of scotorefractoriness. Lesions of the aPVT did not significantly affect the rate or the degree of the short-day-induced decline in serum levels of LH or prolactin, nor the pattern of testicular regression and the subsequent expression of refractoriness.

To enable us to determine whether the aPVT might be involved in the entrainment or the expression of circadian rhythms, locomotor activity was monitored continuously in lesioned and control groups in Experiment 2, prior to and following the switch to short days. The reduction in photoperiod (involving an 8-hr advance in the time of lights-off and an 8-hr extension of the dark phase) caused a decompression of the nocturnal activity bout of control animals, so that after 2 weeks in short days, activity onset had also advanced to regain its phase relationship to the timing of lights-off. A similar pattern of re-entrainment was observed in lesioned animals, and no differences were observed between treatment groups in the rate of entrainment and decompression. In addition, both intact controls and animals bearing large bilateral lesions of the aPVT exhibited robust free-running circadian rhythms of locomotor activity when held under constant dim red light.

In summary, the integrity of the aPVT is not necessary for the seasonal response of the reproductive axis and prolactin secretion to photoperiod, nor for photic entrainment of activity rhythms, in the Syrian hamster.
Circadian Variations in the Amplitude of Corticotropin-Releasing Hormone 41 (CRH41) Episodic Release Measured In Vivo in Male Rats: Correlations with Diurnal Fluctuations in Hypothalamic and Median Eminence CRH41 Contents
Authors: Ixart G. , Siaud P. , Barbanel G. , Mekaouche M. , Givalois L. , Assenmacher I.
Published: March 2007

The possible correlation between the circadian and episodic release of corticotropin-releasing hormone 41 (CRH41) in male rats was explored in a comparative study, including the measurement at 0700 hr and 1700 hr of (1) the quantitative parameters of the episodic release pattern of CRH41 into the push-pull-cannulated median eminence (ME); (2) CRH41 content measured by radioimmunoassay in the hypothalamus, and immunocytochemically in the ME; and (3) plasma adrenocorticotropic hormone (ACTH). The data showed that in early evening, the 3.4-fold rise in plasma ACTH coincided with a doubling of CRH41 content in the hypothalamus and in the ME, and of the CRH41 release from the perfused ME. The immunocytochemical data further indicated that the ME area labeled with CRH41 immunoreactivity, rather than the labeling intensity of CRH41-stained neurons, increased in the evening, which may point to an evening recruitment of additional CRH41-producing neurons as the origin of the evening increment in CRH41 and ACTH releases. Finally, the computerized analysis of the CRH41-releasing pattern with three different algorithms (Pulsar, Ultra, and the Santen and Bardin algorithm) showed for the first time that the evening rise in CRH41 output was associated with correlative increases of three parameters of the episodic pattern—peak amplitude (+ 55% to + 80%), peak duration (+ 20%), and mean absolute peak values (+ 73%)-while the pulse frequency remained at the baseline level of 3 cycles · hr-1. The data suggest the occurrence of a connection between the circadian pacemaker and the machinery generating the episodic release of CRH41.
Influence of Acute Melatonin Treatment and Light on the Circadian Melatonin Rhythm in the Djungarian Hamster
Authors: Yellon Steven M. , Hilliker Sandra
Published: March 2007

The present study tested the hypothesis that acute melatonin treatment affects the biological clock mechanism controlling the circadian melatonin rhythm. Adult Djungarian hamsters were raised in LD 16:8 (lights-on from 0300 to 1900 hr). Pineal and serum melatonin concentrations were assessed at specific clock times during the subsequent LD cycle (day 1) and afterwards in hamsters that remained in constant darkness (day 2), to assess the effects of treatment on the circadian melatonin rhythm. In untreated controls ( n = 76), melatonin increased in the pineal and in circulation within the first hour after lights-off (day 1) or subjective night (day 2); melatonin concentrations remained elevated for up to 7 hr. A single melatonin injection (5 μg/0.2 ml saline, s.c.), administered in the morning (0900 hr, n = 80) or late afternoon (1600 hr, n = 74), transiently increased melatonin in circulation but not in the pineal gland. In constant darkness (day 2), the circadian melatonin rhythm in both the pineal gland and circulation was the same as that in untreated controls. No significant differences were found among the three groups in the mean concentration during the day or night; the rise, fall, peak time, peak amplitude, and duration of increased melatonin were also unchanged. The ability of melatonin to override the effect of a light pulse on the circadian melatonin rhythm was also tested. The 5-min light pulse at night (2300-2305 hr of day 1, n = 64) delayed the rise and shortened the duration of increased melatonin in both pineal gland and serum by as much as 3 hr (day 2); these light effects were more pronounced on the pineal than on the serum melatonin rhythm. Injection with melatonin prior to the light pulse (5 μg/0.2 ml saline at 2245 hr, n = 64) failed to alter the inhibitory effects of light on the circadian melatonin rhythm. These data suggest that the biological clock mechanism controlling the circadian melatonin rhythm in the Djungarian hamster in long days is responsive to the phase-shifting effects of light, but resistant to the influence of acute melatonin treatment.
Different Phase Responses of the Two Circadian Oscillators in Gonyaulax
Authors: Morse David , Hastings J. Woodland , Roenneberg Till
Published: March 2007

Two circadian oscillators have been previously shown to exist in the unicellular alga Gonyau lax polyedra by virtue of different periods for two different rhythms, which occur under certain experimental conditions. Here we show that phase shifts in response to light pulses also differ for these two rhythms. The phase response curves (PRCs) for white or blue light pulses are similar in shape and amplitude, but are somewhat displaced in time and have a slightly larger delay portion for the aggregation rhythm, corresponding to the A oscillator. In contrast, the aggregation rhythm PRC for dark pulses in a red light background has a much larger amplitude than that for the bioluminescence rhythm (B oscillator). These results suggest that the light input mechanism of the B oscillator is mainly blue-sensitive, whereas that of the A oscillator is sensitive to both red and blue light. This is supported by entrainment experiments: Dark pulses given as a skeleton 24-hr scotoperiod in a blue light background act as a strong zeitgeber for both oscillators. But if red light is used as background, there is bistability in the entrainment of the B oscillator, whereas the A oscillator is entrained to a definitive phase angle, regardless of the cells' prior phase of entrainment. Finally, the two oscillators can be differentially entrained with 22-hr T cycles using 3-hr dark pulses interrupting red light (19 hr), whereas both oscillators are entrained when the dark pulses interrupt blue light.
Subjective Alertness Rhythms in Elderly People
Authors: Monk Timothy H. , Buysse Daniel J. , Reynolds Charles F. , Kupfer David J. , Houck Patricia R.
Published: March 2007

The aim of this study was to evaluate age-related changes in the circadian rhythm of subjective alertness and to explore the circadian mechanisms underlying such changes. Using a visual analogue scale (VAS) instrument, 25 older men and women (71 y and older; 15 female, 10 male) rated their subjective alertness about 7 times per day during 5 baseline days of temporal isolation during which habitual bedtimes and waketimes were enforced. Comparisons were made with 13 middle-aged men (37-52 y) experiencing the same protocol. Advancing age (particularly in the men) resulted in less rhythmic alertness patterns, as indicated by lower amplitudes and less reliability of fitted 24-h sinusoids. This appeared in spite of the absence of any reliable age-related diminution in circadian temperature rhythm amplitude, thus suggesting the effect was not due to SCN weakness per se, but to weakened transduction of SCN output. In a further experiment, involving 36 h of constant wakeful bedrest, differences in the amplitude of the alertness rhythm were observed between 9 older men (79 y+), 7 older women (79 y+), and 17 young controls (9 males, 8 females, 19-28 y) suggesting that with advancing age (particularly in men) there is less rhythmic input into subjective alertness from the endogenous circadian pacemaker. These results may explain some of the nocturnal insomnia and daytime hypersomnia that afflict many elderly people.
An Urban View: Catherine Bauer's Five Questions
Authors: Birch Eugenie Ladner
Published: March 2007

Catherine Bauer, recently designated a "planning pioneer" by the American Instilute of Certified Planners, was a major theorist in the field of planning between 1934 and 1964, a critical era for the profession. Her inf luence rested on a variety of positions that she took in her writing. This paper surveys this work and shows how she focused on five questions treating housing, urban redevelopment, regional planning, suburbanization, social planning, and urbanization in the third world. No one in the profession today is duplicating Bauer's role as an observer and critic of the urban world.
Models of Housing Adjustment and Their Implications for Planning and Policy
Authors: Quercia Roberto G. , Rohe William M.
Published: March 2007

This article describes existing housing adjustment theoryand assesses its adequacy in explaining the housing adjustment behaviors of households. The evolution of housing adjustment theory is divided into four stages: (1) the earlier models of rural-to-urban migration, (2) the models of intraurban mobility, (3) the models of the nonmoving adjustment decision, and (4) the more comprehensive models of housing adjustment that include both moving and nonmoving adjustment mechanisms within a single framework. The implications of these models for planningand policy arediscussed, along with suggestions for future research.
Planning for Collaborative Neighborhood Problem-Solving: A Review of the Literature
Authors: Julian David A.
Published: March 2007

This review addresses a number of questions concerning collaborative neighborhood problem-solving. Theoretical conceptualizations, case studies, and empirical literature are reviewed in an effort to understand the nature of the collaborative process. Although this review focuses on mandated collaboration in human services activities, the information is relevant to a wide variety of planning applications. A model for neighborhood-based collaborative problem-solving developedfor the United Way of Franklin County is also presented.
Achieving Sustainability: Reform or Transformation?
Authors: Rees William E.
Published: March 2007

We have reached a unique juncture in human ecological history, one requiring a radical reconfiguration of planning values and goals. The "ecological footprint" of the global economy is already larger than the planet, yet a quarter of humanity still lives in poverty, the human family is expanding by 90 million a year, and material demands everywhere are rising. An unlikely tenfold reduction in the energy and material intensity of economic activity would be required to accommodate anticipated economic growth safely, posing an enormous challenge to planners in facilitating the transition to sustainability. Failure enhances the considerable possibility of global disaster.
Infrastructure of the "New Age": Telecommunications Planning
Authors: Bradbury Susan L. , Becker Barbara
Published: March 2007

Infrastructure building, maintenance, and financing are familiar issues to planners, but only recently has the relationship between economic development and the quality and quantity of infrastructure received much attention. Largely absentfrom this emerging economic development/infrastructure literature, however, is discussion of the importance of telecommunications infrastructure. As the U.S. economy moves away from traditional manufacturing and toward a reliance on knowledge-intense, high-tech servicefirms, access to this infrastructure will be an increasingly criticalfactor in the location of both commercial and residential development. To attract and retain the communications-dependent firms and industries that are driving the information economy, state and local planners must actively provide access to the telecommunications services that these businesses and their skilled laborforces will demand. Clearly, communities must begin to planfor and provide telecommunications infrastructure to promote economic development if they are to avoid being left behind as the United States competes in the internationally based information economy.
Highways and Economic Productivity: Interpreting Recent Evidence
Authors: Boarnet Marlon G.
Published: March 2007

This article reviews the recent literature on public infrastructure and economic productivity, with special attention to the particular case of highway infrastructure. Recent evidence suggests that, at the margin, highway infrastructure contributes little to state or national productivity. This is consistent with studies that show relatively small land-use impactsfrom modem highways. Yet the idea that highways enhance economic health is common in the policy and planning communities. Two explanations can help reconcile this divergence between academic research and popular perception. First, some of the economic development observed near highways might not actually be caused by the highway. Second, some of the economic development near highways might be a shift of economic activity awayfrom other areas. Either explanation implies the need for reforms in highway project analysis and funding. This article suggests appropriate policy reforms and directions for future research.
Enterprises, External Economies, and Economic Development
Authors: Feser Edward J.
Published: March 2007

There has recently been a revival of interest in the planning community in the role of interfirm synergies, externalities, and spillovers as sources of competitive advantage for groups of colocated businesses (e.g., in industrial districts, clusters, and complexes). An increasing number of cities and states are adopting a variety of economic development planning initiatives based on the advantages of geographic concentration. This article reviews and critiques the central theoretical and empirical approaches to the concept of spatial external economies and the firm, with a view toward clarifying the core range of definitions and perspectives. It suggests that these often competing perspectives must be better meshed to yield richer and more robust planning and policy prescriptions.