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Terms modified by Daytime Selected AbstractsCircadian Variation in Heart-Rate Variability in Localization-related EpilepsyEPILEPSIA, Issue 5 2007Håkan Persson Summary:,Purpose: Case,control studies of sudden unexpected death in epilepsy (SUDEP) have reported that SUDEP is more likely to occur during sleep and thus presumably during night hours. The circadian variation of heart-rate variability (HRV) might be of relevance to this risk. We examined night versus daytime HRV in patients with newly diagnosed and refractory localization-related epilepsy, assessing the effects of drug treatment and epilepsy surgery on the night/daytime HRV ratio. Methods: We used spectral analysis to assess HRV and calculated the night-time (00.00,05.00)/daytime (07.30,21.30) ratio of HRV in 14 patients with newly diagnosed localization-related epilepsy before and during carbamazepine (CBZ) treatment and in 21 patients with temporal lobe epilepsy before and after epilepsy surgery. Both groups were compared with age- and sex-matched controls. Results: No significant differences were found from controls in the night/daytime ratios of HRV whether compared before or after initiation of treatment with CBZ in newly diagnosed epilepsy patients. When patients were used as their own controls, night/daytime ratios of standard deviation of RR intervals (p = 0.04) and total power (p = 0.04) were significantly lower during treatment than before. Compared with those of controls, the night/daytime ratios were lower in epilepsy surgery patients before surgery [low-frequency power (p = 0.04); high-frequency power (p = 0.04)]. Night/daytime ratios did not change significantly after surgery. Conclusions: The HRV of the patients was more affected during night-time when the risk of SUDEP seems to be highest in such patients. [source] Hourly and daily clearness index and diffuse fraction at a tropical station, Ile-Ife, NigeriaINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 8 2009E. C. Okogbue Abstract Dataset consisting of hourly global and diffuse solar radiation measured over the period February 1992 and December 2002 have been utilized to investigate the diurnal and seasonal variations of hourly and daily clearness index together with the diffuse fraction at a tropical station Ile-Ife (7.5°N, 4.57°E), Nigeria. Statistical analysis (the frequency and cumulative frequency distribution of the hourly and daily clearness index) and subsequent characterization of the sky conditions over the station based on these were also done, and their implications for solar energy utilization in the area discussed. Daytime (11:00,15:00 LST) monthly mean hourly diffuse fraction, M,d (explained in a separate ,List of Symbols' provided, along with other symbols used in this article), have values, which are most of the time less than 0.52, 0.54 and 0.60 respectively for January, February and March in the dry season. However, during the months of July and August (which are typical of the wet season), the values range between 0.61 and 0.85 (being generally greater than 0.65) with the corresponding values of the monthly mean hourly clearness index, M,T, ranging between 0.23 and 0.45. Statistical analysis of hourly and daily clearness index showed that the local sky conditions at the station were almost devoid of clear skies and overcast skies (clear skies and overcast skies occurred for only about 3.5% and 4.8% of the time respectively). The sky conditions were rather predominantly cloudy (cloudy skies occurred for about 88% of the time) all the year round. Copyright © 2009 Royal Meteorological Society [source] Dietary poorly absorbed, short-chain carbohydrates increase delivery of water and fermentable substrates to the proximal colonALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 8 2010J. S. BARRETT Summary Background, Functional gut symptoms are induced by inclusion and reduced by dietary restriction of poorly absorbed short-chain carbohydrates (FODMAPs), but the mechanisms of action remain untested. Aims, To determine the effect of dietary FODMAPs on the content of water and fermentable substrates of ileal effluent. Methods, Twelve ileostomates without evidence of small intestinal disease undertook two 4-day dietary periods, comprising diets differing only in FODMAP content in a randomized, cross-over, single-blinded intervention study. Daytime (14 h) ileal effluent was collected on day four of each diet. Patients rated effluent volume and consistency on a 10-cm visual analogue scale. The FODMAP content of the diet and effluent was measured. Results, Ingested FODMAPs of 32% (range 6,73%) was recovered in the high FODMAP diet effluent. Effluent collection weight increased by a mean of 22% (95% CI, 5,39), water content by 20% (2,38%) and dry weight by 24% (4,43%) with the high compared to low FODMAP diet arm. Output increased by 95 (28,161) mL. Volunteers perceived effluent consistency was thicker (95% CI, 0.6,1.9) with the low FODMAP diet than with the high FODMAP diet (3.5,6.1; P = 0.006). Conclusions, These data support the hypothetical mechanism; FODMAPs increase delivery of water and fermentable substrates to the proximal colon. [source] Silicone Gel Sheeting for the Management and Prevention of OnychocryptosisDERMATOLOGIC SURGERY, Issue 3 2003A. Burhan Aksakal MD BACKGROUND Onychocryptosis, commonly referred to as ingrown nails, has many therapeutic alternatives for its management. Although mild cases can be treated conservatively, in severe cases, surgical treatment is preferred. Silicone gel sheeting is found to be effective in the treatment of hypertrophic scars and keloids. OBJECTIVE To document the effectiveness of silicone gel sheeting in the management of patients with onychocryptosis and in the prevention of the recurrences by breaking the devil's circle, which usually took place after the surgical procedures used in the treatment of the onychocryptosis. METHODS Fourteen patients were enrolled in the study. Entry criteria required the presence of slight (2 patients), moderate (2 patients), or severe (10 patients) onychocryptosis. The simple technique used in the study was the excision of the one-quarter part of the lesional side of the nail plate without excising the granulation tissue. After 24 hours, the silicone was placed on the granulation tissue and the exposed nail bed. Silicone gel sheet was bandaged loosely without applying any pressure. Patients entering the study were given detailed instructions in applying and using the gel for 12 hours during the daytime. The study lasted for 14 months and was composed of a treatment period of 4 months and a follow-up period of 10 months. The patients were evaluated every 2 weeks in the first month and then monthly. The change in thickness of granulation tissue was evaluated by comparing them with the baseline photographs and those taken at each visit. RESULTS The management and prevention of onychocryptosis were achieved in 12 of 14 patients (85.71%). The silicone gel sheeting treatment was well tolerated except for an occasional transient exudation, which was resolved when the treatment was withdrawn. CONCLUSION The results show that the new method that we used for the treatment of onychocryptosis is successful in reducing the thickness of the hypertrophic nail fold and prevents the recurrence of the condition during the regrowth of the nail plate by breaking the devil's circle. The advantage of this method is that it is not destructive to the nail matrix and the adjacent tissue. [source] Lotic dispersal of lentic macroinvertebratesECOGRAPHY, Issue 2 2006Frank Van de Meutter Little is known on dispersal of lentic macroinvertebrates. We quantified dispersal of lentic macroinvertebrates through pond connections in a highly connected pond system, and investigated how dispersal rates were affected by connection properties and time of the day (day, night). Furthermore, by comparing the composition of assemblages of dispersing macroinvertebrates with the macroinvertebrate assemblages of source ponds, we tested whether dispersal was neutral or a taxon-specific process. We found that many taxa dispersed through the pond connections. Taxa richness of the dispersing macroinvertebrate assemblage was proportional to taxa richness in the source ponds. The number of individuals that dispersed, however, was not related to source pond densities, possibly because of the highly patchy distribution of lentic macroinvertebrates within ponds. Elevated dispersal rates were recorded for Baetidae, Chironomidae and Physidae, indicating a taxon-specific use of pond connections as dispersal pathway. None of the physical properties of the connections affected dispersal. Macroinvertebrates dispersed more during the night than during daytime. Of seven tested families, Chaoboridae and Chironomidae showed higher dispersal during the night, probably resulting from diel vertical migration, since pond connections mainly transported near-surface water. Flying and non-flying invertebrates dispersed equally frequent through pond connections. For non-flying invertebrates that disperse infrequently over land, dispersal through pond connections may provide an important additional means of dispersal. [source] Finnegan neonatal abstinence scoring system: normal values for first 3 days and weeks 5,6 in non-addicted infantsADDICTION, Issue 3 2010Urs Zimmermann-Baer ABSTRACT Objective The neonatal abstinence scoring system proposed by Finnegan is used widely in neonatal units to initiate and to guide therapy in babies of opiate-dependent mothers. The purpose of this study was to assess the variability of the scores in newborns and infants not exposed to opiates during the first 3 days of life and during 3 consecutive days in weeks 5 or 6. Patients and methods Healthy neonates born after 34 completed weeks of gestation, whose parents denied opiate consumption and gave informed consent, were included in this observational study. Infants with signs or symptoms of disease or with feeding problems were excluded. A modified scoring system was used every 8 hours during 72 hours by trained nurses; 102 neonates were observed for the first 3 days of life and 26 neonates in weeks 5,6. A meconium sample and a urine sample at weeks 5,6 were stored from all infants to be analysed for drugs when the baby scored high. Given a non-Gaussian distribution the scores were represented as percentiles. Results During the first 3 days of life median scores remained stable at 2 but the variability increased, with the 95th percentile rising from 5.5 on day 1 to 7 on day 2. At weeks 5,6 median values were higher during daytime (50th percentile = 5, 95th percentile = 8) than night-time (50th percentile = 2, 95th percentile = 6, P = 0.02). Conclusion Scores increase from days 1,3 to weeks 5,6 and show day,night cycles with 5,6 weeks. Values above 8 can be considered pathological. This data may help to raise suspicion of narcotic withdrawal and to guide therapy. [source] Autoinducers extracted from microbial mats reveal a surprising diversity of N -acylhomoserine lactones (AHLs) and abundance changes that may relate to diel pHENVIRONMENTAL MICROBIOLOGY, Issue 2 2009Alan W. Decho Summary Microbial mats are highly structured and diverse communities, and one of the earliest-known life assemblages. Mat bacteria interact within an environment marked by strong geochemical gradients and fluctuations. We examined natural mat systems for the presence of autoinducers involved in quorum sensing, a form of cell,cell communication. Our results revealed that a diverse array of N -acylhomoserine lactones (AHLs) including C4 - to C14 -AHLs, were identified from mat extracts using mass spectrometry (MS), with further confirmation by MS/MS-collision-induced dissociation (CID), and additions of external standards. Microelectrode measurements showed that mats exhibited diel pH fluctuations, ranging from alkaline (pH 9.4) during daytime (net photosynthesis) to acidic (pH 6.8) during darkness (net respiration/fermentation). Under laboratory conditions, AHLs having shorter acyl-chains were degraded within the time frame that daily alkaline pH (> 8.2) conditions exist in mats. Intensive sampling of mats after full day- or night-time incubations revealed that accumulations of extractable shorter-chain AHLs (e.g. C8 - and C10 -AHLs) were significantly (P < 0.001) diminished during daytime. Our study offers evidence that stabilities of AHLs under natural conditions may be influenced by the proximal extracellular environment. We further propose that the ancient periodicity of photosynthesis/respiration in mats may potentially drive a mechanism for diel differences in activities of certain autoinducers, and hence bacterial activities mediated through quorum sensing. [source] Comparative study of microcystin-LR-induced behavioral changes of two fish species, Danio rerio and Leucaspius delineatusENVIRONMENTAL TOXICOLOGY, Issue 6 2004Daniela Baganz Abstract The spontaneous locomotor behavior separated into day/night activity phases of two fish species Danio rerio and Leucaspius delineatus was recorded and quantified continuously under sublethal long-term exposure to microcystin-LR in tanks. Microcystin-LR was applied in concentrations of 0.5, 5, 15, and 50 ,g L,1. By using an automated video-monitoring and object-tracing system, the average motility (swimming velocity) and the average number of turns were assessed. Clear dose-dependent effects of microcystin-LR on the behavior of both test fish were measured. During the daytime, the motility of Danio rerio as well as Leucaspius delineatus increased significantly by exposure to the lowest concentrations, whereas higher concentrations led to significantly decreased motility. Influenced by microcystin-LR, the swimming time of Leucaspius delineatus reversed, going from a prominently diurnal activity to a nocturnal one; Danio rerio remained active during the daytime. Most of the relative changes in the behavioral patterns of Danio rerio and Leucaspius delineatus suggest these fish have comparable susceptibility to microcystin-LR and may indicate some adverse consequences for fish populations, for example, in connection with reproduction and predator,prey interactions. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 564,570, 2004. [source] Statistical analysis of temperature impact on daily hospital admissions: analysis of data from Udine, ItalyENVIRONMETRICS, Issue 1 2006Francesco Pauli Abstract This article is devoted to the analysis of the relationship between the health status of an urban population and meteorological variables. The analysis considers daily number of hospital admissions, not due to surgery, regarding the population resident in the Municipality of Udine, aged 75 and over. Hourly records on temperature, humidity, rain, atmospheric pressure, solar radiation, wind velocity and direction recorded at an observation site located near the center of Udine are considered. The study also considers hourly measures of pollutant concentrations collected by six monitoring stations. All data are relative to the summer periods of years 1995,2003. Generalized additive models (GAM) are used in which the response variable is the number of hospital admissions and is assumed to be distributed as a Poisson whose rate varies as a possibly non-linear function of the meteorological variables and variables allowing for calendar effects and pollutant concentrations. The subsequent part of the analysis explores the distribution of temperature conditional on the number of daily admissions through quantile regression. A non-linear (N-shaped) relationship between hospital admissions and temperature is estimated; temperature at 07:00 is selected as a covariate, revealing that nighttime temperature is more relevant than daytime. The quantile regression analysis points out, as expected, that the distribution of temperature on days with more admissions has higher q -quantiles with q near unity, while a clear-cut conclusion is not reached for q quantiles with q near 0. Copyright © 2005 John Wiley & Sons, Ltd. [source] Effect of digoxin on circadian blood pressure values in patients with congestive heart failureEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 4 2000Kirch Background The aim of the study was to investigate the effect of chronic digoxin treatment on circadian blood pressure profile in normotensive patients with mild congestive heart failure. Methods In a randomized double-blind, placebo-controlled cross-over protocol, 12 normotensive patients with mild congestive heart failure took digoxin or placebo for a total of 7 days. Automatic 24-h ambulatory blood pressure measurements were carried out at day 7, of either digoxin or placebo. Results Diastolic blood pressure significantly decreased and systolic blood pressure significantly increased during overnight sleep in the digoxin phase compared to placebo. Digoxin had no effect on either systolic or diastolic blood pressure during daytime. Heart rate decreased in the overnight sleeping phase but did not differ significantly between placebo and digoxin phase. Conclusions Digoxin significantly decreases diastolic blood pressure during overnight sleep in patients with congestive heart failure. This effect is likely to be caused by reduction of sympathetic activity or increase of parasympathetic activity. Increase of systolic blood pressure during sleep is probably caused by the positive inotropic effect of the drug. [source] Effect of daytime, weekday and year of admission on outcome in acute ischaemic stroke patients treated with thrombolytic therapyEUROPEAN JOURNAL OF NEUROLOGY, Issue 4 2010M. Jauss Background:, Since doubts were raised, if a challenging medical procedure such as acute stroke treatment including thrombolysis with recombinant tissue plasminogen activator (rTPA) is available with identical standard and outcome 24 h and 7 days a week our aim was to examine if acute stroke patients defined by onset-admission time (OAT) of , 3 h were treated differently or had distinct outcome when admitted during off duty hours (day versus night and weekend versus weekdays) and if any differences in treatment or outcome were apparent when comparing patients admitted in the year 2003 with patients admitted in the year 2006. Methods:, We analyzed 2003,2006 data of a prospective registry and grouped patients by time, day, and year of admission. The evaluation was limited to patients that were diagnosed with ischaemic stroke and with OAT of , 3 h. Medical and sociodemographic items, use of thrombolytic treatment, complications during clinical course and place of discharge were obtained. Clinical state on admission and discharge was assessed using the modified Rankin scale. Comparison with chi-square test, t -test and logistic regression was performed. Results:, Patient's characteristics, rate of thrombolysis, and outcome were independent from time or day of admission. Proportion of patients with good clinical state at discharge increased significantly from 2003 to 2006 together with a higher rate of rTPA treatment without increase of intracranial hemorrhage. Proportion of patients discharged in good clinical condition after rTPA treatment increased from 34% to 44%. Conclusions:, Stroke treatment in potential candidates for thrombolytic therapy revealed no impairment on weekend or at night already in 2003. During 4 years, it was possible to increase rate of rTPA treatment from 8.9% to 21.8% without increment of complications or death, confirming that rTPA is safe and can be implemented with full daily and weekly coverage. [source] Tissue-type plasminogen activator-plasmin-BDNF modulate glutamate-induced phase-shifts of the mouse suprachiasmatic circadian clock in vitroEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2009Xiang Mou Abstract The mammalian circadian clock in the suprachiasmatic nucleus (SCN) maintains environmental synchrony through light signals transmitted by glutamate released from retinal ganglion terminals. Brain-derived neurotrophic factor (BDNF) is required for light/glutamate to reset the clock. In the hippocampus, BDNF is activated by the extracellular protease, plasmin, which is produced from plasminogen by tissue-type plasminogen activator (tPA). We provide data showing expression of proteins from the plasminogen activation cascade in the SCN and their involvement in circadian clock phase-resetting. Early night glutamate application to SCN-containing brain slices resets the circadian clock. Plasminogen activator inhibitor-1 (PAI-1) blocked these shifts in slices from wild-type mice but not mice lacking its stabilizing protein, vitronectin (VN). Plasmin, but not plasminogen, prevented inhibition by PAI-1. Both plasmin and active BDNF reversed ,2 -antiplasmin inhibition of glutamate-induced shifts. ,2 -Antiplasmin decreased the conversion of inactive to active BDNF in the SCN. Finally, both tPA and BDNF allowed daytime glutamate-induced phase-resetting. Together, these data are the first to demonstrate expression of these proteases in the SCN, their involvement in modulating photic phase-shifts, and their activation of BDNF in the SCN, a potential ,gating' mechanism for photic phase-resetting. These data also demonstrate a functional interaction between PAI-1 and VN in adult brain. Given the usual association of these proteins with the extracellular matrix, these data suggest new lines of investigation into the locations and processes modulating mammalian circadian clock phase-resetting. [source] Effect of Exogenous Melatonin on Mood and Sleep Efficiency in Emergency Medicine Residents Working Night ShiftsACADEMIC EMERGENCY MEDICINE, Issue 8 2000Milan Jockovich MD Abstract. Objective: To determine whether melatonin taken prior to attempted daytime sleep sessions will improve daytime sleep quality, nighttime sleepiness, and mood state in emergency medicine (EM) residents, changing from daytime to nighttime work schedules. Methods: A prospective, randomized, double-blind crossover design was used in an urban emergency department. Emergency medicine residents who worked two strings of nights, of at least three nights' duration each, and separated by at least one week of days were eligible. Subjects were randomized to receive either melatonin 1 mg or placebo, 30 to 60 minutes prior to their daytime sleep session, for three consecutive days after each night shift. Crossover to the other agent occurred during their subsequent night shifts. Objective measures of quality of daytime sleep were obtained using the Actigraph 1000. This device measures sleep motion and correlates with sleep efficiency, total sleep time, time in bed, and sleep latency. The Profile of Mood States (POMS) and the Stanford Sleepiness Scale (SSS) were also used to quantify nighttime mood and sleepiness. Results: Among the 19 volunteers studied, there was no difference in sleep efficiency (91.16% vs 90.98%, NS), sleep duration (379.6 min vs 342.7 min, NS), or sleep latency (7.59 min vs 6.80 min, NS), between melatonin and placebo, respectively. In addition, neither the POMS total mood disturbance (5.769 baseline vs 12.212 melatonin vs 5.585 placebo, NS) nor the SSS (1.8846 baseline vs 2.2571 melatonin vs 2.1282 placebo, NS) demonstrated a statistical difference in nighttime mood and sleepiness between melatonin and placebo. Conclusions: There are no beneficial effects of a 1-mg melatonin dose on sleep quality, alertness, or mood state during night shift work among EM residents. [source] Reducing sea turtle by-catch in pelagic longline fisheriesFISH AND FISHERIES, Issue 1 2006Eric Gilman Abstract Reducing by-catch of sea turtles in pelagic longline fisheries, in concert with activities to reduce other anthropogenic sources of mortality, may contribute to the recovery of marine turtle populations. Here, we review research on strategies to reduce sea turtle by-catch. Due to the state of management regimes in most longline fisheries, strategies to reduce turtle interactions must not only be effective but also must be commercially viable. Because most research has been initiated only recently, many results are not yet peer-reviewed, published or readily accessible. Moreover, most experiments have small sample sizes and have been conducted over only a few seasons in a small number of fisheries; many study designs preclude drawing conclusions about the independent effect of single factors on turtle by-catch and target catch rates; and few studies consider effects on other by-catch species. In the US North Atlantic longline swordfish fishery, 4.9-cm wide circle hooks with fish bait significantly reduced sea turtle by-catch rates and the proportion of hard-shell turtles that swallowed hooks vs. being hooked in the mouth compared to 4.0-cm wide J hooks with squid bait without compromising commercial viability for some target species. But these large circle hooks might not be effective or economically viable in other longline fisheries. The effectiveness and commercial viability of a turtle avoidance strategy may be fishery-specific, depending on the size and species of turtles and target fish and other differences between fleets. Testing of turtle avoidance methods in individual fleets may therefore be necessary. It is a priority to conduct trials in longline fleets that set gear shallow, those overlapping the most threatened turtle populations and fleets overlapping high densities of turtles such as those fishing near breeding colonies. In addition to trials using large 4.9-cm wide circle hooks in place of smaller J and Japan tuna hooks, other fishing strategies are under assessment. These include: (i) using small circle hooks (, 4.6-cm narrowest width) in place of smaller J and Japan tuna hooks; (ii) setting gear below turtle-abundant depths; (iii) single hooking fish bait vs. multiple hook threading; (iv) reducing gear soak time and retrieval during daytime; and (v) avoiding by-catch hotspots through fleet communication programmes and area and seasonal closures. [source] Seasonal variation in habitat use by salmon, Salmo salar, trout, Salmo trutta and grayling, Thymallus thymallus, in a chalk streamFISHERIES MANAGEMENT & ECOLOGY, Issue 4 2006W. D. RILEY Abstract, A portable multi-point decoder system deployed in a tributary of the River Itchen, a southern English chalk stream, recorded the habitats used by PIT-tagged juvenile salmon, Salmo salar L., trout, Salmo trutta L. and grayling, Thymallus thymallus L., with a high degree of spatial and temporal resolution. The fishes' use of habitat was monitored at 350 locations throughout the stream during September/October 2001 (feeding period) and January/February 2002 (over-wintering period). Salmon parr tended to occupy water 25,55 cm deep with a velocity between 0.4 and 1.0 m s,1. During both autumn and winter, first year salmon (0+ group) were associated with gravel substrate during the daytime and aquatic weed at night. In autumn, 1+ salmon were strongly associated with hard mud substrates during the day and with marginal tree roots at night. In winter, they were located on gravel substrate by day and gravel and mud at night. Trout were associated with a greater range of habitats than salmon, generally occupying deeper and faster water with increasing age. During the autumn, 0+ trout were located along shallow (5,10 cm) and slow (,0.1,0.4 m s,1) margins of the stream, amongst tree roots by day and on silty substrates at night. During winter the 0+ trout occupied silty substrates at all times. As age increased, trout increasingly used coarse substrates; hard mud, gravel and chalk, and weed at night. All age groups of grayling (0+, 1+ and 2+) tended to occupy hard gravel substrate at all times and used deeper and faster water with increasing age. The 1+ and 2+ groups were generally found in water 40,70 cm deep with a velocity between 0.3 and 0.5 ms,1, whilst the 0+ groups showed a preference for shallower water with reduced velocity at night, particularly in the winter. There were greater differences in the habitats used between species and age groups than between the autumn and winter periods, and the distribution of fish was more strongly influenced by substrate type than water depth or velocity. The results are discussed in relation to the habitat requirements of mixed salmonid populations and habitat management. [source] Annual cycle of clupeiform larvae around Gran Canaria Island, Canary IslandsFISHERIES OCEANOGRAPHY, Issue 4 2006P. BÉCOGNÉE Abstract The distribution and abundance of fish larvae was studied along the eastern and southern shelf of Gran Canaria Island (Canary Islands) from July 2000 to June 2001. Oblique bongo hauls were carried out fortnightly during the daytime, coinciding with days of full and new moon. During February, the area was sampled every 2,5 days. About 17.3% of the ichthyoplanktonic community was composed of clupeiform larvae: 92.9% of these larvae were Sardinella aurita, whereas 4.7% and 2.4% were respectively Engraulis encrasicolus and Sardina pilchardus. Sardinella aurita larvae appeared during the whole year with two periods of maximum abundance: June to September and December to February. During the full moon their abundance was on average 38.5% (±6.8%) of their numbers during the new moon, showing a clear lunar periodicity. Engraulis encrasicolus larvae appeared from November to March, also coinciding with the new moon. Sardina pilchardus larvae only appeared during two short periods, both coinciding with filaments shed from the African coastal upwelling which reached the island. This fact confirms the transport of fish larvae from the upwelling area off northwest Africa to the Canary Islands, promoting a genetic flow among both sites. [source] Spatial distribution of the Japanese common squid, Todarodes pacificus, during its northward migration in the western North Pacific OceanFISHERIES OCEANOGRAPHY, Issue 2 2006ATSUSHI KAWABATA Abstract The spatial distribution of Todarodes pacificus in and near the Kuroshio/Oyashio Transition Zone during its northward migration was examined by comparative surveys using two types of mid-water trawl net and supplementary squid jigging from June to July 2000. The vertical and horizontal distribution patterns varied for different body sizes in relation to the oceanographic structure. Todarodes pacificus of 1,20 cm dorsal mantle length (ML) were widely distributed from the coastal waters of Japan to near 162°E longitude, probably due to transport by the Kuroshio Extension (KE). Todarodes pacificus smaller than 10 cm ML were mainly distributed in temperate surface layers at sea surface temperatures (SSTs) >15°C near the KE meander probably because of their poor tolerance to lower temperatures and limited swimming ability. Squid of 10,15 cm ML were distributed in the offshore waters of 10,15°C SST and in the coastal waters of northern Honshu, and underwent diel vertical migrations between the sea surface at night and deeper layers during the daytime. Squid larger than 15 cm ML were distributed in the coastal feeding grounds of northern Honshu and Hokkaido until they began their southward spawning migration. They also underwent diel vertical migrations, but remained deeper at night than the squid of 10,15 cm ML; this migration pattern closely matched that of their main prey such as euphausiids. We concluded that as T. pacificus grow, they shift their distribution range from the temperate surface layer around the KE toward the colder deeper layers, above 5°C, in the Oyashio and coastal areas. [source] Carbon dioxide uptake, water relations and drought survival for Dudleya saxosa, the ,rock live-forever', growing in small soil volumesFUNCTIONAL ECOLOGY, Issue 4 2007P. S. NOBEL Summary 1Although many plants grow in rock crevices and other regions of small soil volume, including over 20 000 epiphytic and hemi-epiphytic species, analyses of the actual soil volume occupied, the water availability in that soil, the water-storage capacity in the shoots and underground organs, and the photosynthetic pathway utilized have rarely been combined. 2Dudleya saxosa (M.F. Jones) Britton and Rose (Crassulaceae), growing in the Sonoran Desert, has very shallow roots that occupied soil volumes averaging only 43 × 10,6 m3 per medium-sized plant. This volume of soil can hold about the same amount of water (10 g) as can be stored in the leaves, corm and roots combined (11 g), but at a sufficiently high water potential for transfer to the plant for less than 1 week after a substantial rainfall. 3About 80% of the net carbon dioxide uptake by D. saxosa over a 24-h period occurred during the daytime (C3) under wet conditions, the daily total decreasing by 34% and the pattern shifting to nocturnal net CO2 uptake (CAM) after 46 days' drought. Seventy-seven days' drought eliminated its daily net CO2 uptake. 4Stomatal frequency was only 67 mm,2 on the adaxial (upper) surface and twofold lower on the abaxial surface. The cuticle was thick, 34 µm for the adaxial surface. Leaves had 24 mesophyll cell layers, leading to a high mesophyll cell surface area per unit leaf area of 142. 5The three leaf anatomical features plus utilization of CAM increased net CO2 uptake per unit of water transpired, and helped D. saxosa thrive in a small soil volume, with the underground corm being a major supplier of water to the succulent leaves during 2.5 months of drought. The maximum water-holding capacity of the soil explored by the roots closely matched the maximum water-holding capacity of the plant, reflecting the conservative strategy used by D. saxosa in a stressful semi-arid environment. [source] Nest attentiveness and egg temperature do not explain the variation in incubation periods in tropical birdsFUNCTIONAL ECOLOGY, Issue 4 2004B. I. TIELEMAN Summary 1The wide range in incubation periods among bird species has puzzled biologists for decades, because an extended egg-phase increases time-dependent mortality of the eggs. 2We investigated a recently proposed mechanistic explanation inspired by life-history theory, suggesting that adults may increase their own survival by reducing nest attentiveness, the percentage of daytime spent incubating eggs, in exchange for reduced offspring (egg) survival due to a longer incubation period. Incubation behaviour and egg temperatures (Tegg) of 14 bird species in the humid lowland tropics were studied to test the hypothesis that lower nest attentiveness and reduced Tegg cause longer incubation periods. 3Increased nest attentiveness correlated with higher average Tegg. However, neither nest attentiveness nor average Tegg was associated with the length of the incubation period. Longer off-bouts resulted in lower Tegg, but neither number of off-bouts nor off-bout length was associated with incubation period. In addition, we reanalysed a previously published negative association between Tegg and incubation period based on literature data from temperate passerine birds using a larger data set and found no significant correlation. 4In conclusion, our results do not support the hypothesis that longer incubation periods are caused by reduced nest attentiveness and corresponding lower Tegg. [source] Measuring natural abundance of 13C in respired CO2: variability and implications for non-invasive dietary analysisFUNCTIONAL ECOLOGY, Issue 6 2001S. E. PERKINS Summary 1,Three experiments were performed, using laboratory mice (Mus musculus) as a model species, to evaluate the potential of using measurements of carbon isotope ratios in expired CO2 for tracing diets. 2,Breath 13C signatures of mice fed a constant diet (,21·4, ± 0·35) reflected their diet, but were depleted by on average ,5·7,. Body mass, sex and age were independent and significant factors correlated with the variability of 13C enrichment in respired CO2. 3,Breath 13C signatures from starved mice (7 h) were lower than unstarved mice by 2·0,. Subsequently when starved mice were fed a small meal of a new diet, breath 13C signatures approached those of the new diets within 15 min, returning to preingestion levels after 105 min. 4,After a permanent diet switch 13C values of breath were not asymptotic within 6 days, possibly because of use of fat reserves during the daytime carrying an isotopic memory of the previous diet. Hence, individual breath 13C signatures may vary according to nutritive state and previous dietary history. 5,Interindividual variability was measured at 3·3,. The implications are that large samples of individuals will be required to distinguish between diets of different populations where the isotopic difference between their diets was small , for example, that expected between herbivorous and carnivorous diets. However, breath would be suitable for distinguishing between dietary intakes of individuals for food types that are isotopically more distinct , such as between C3 and C4 plants. [source] Wadi Bakht revisited: Holocene climate change and prehistoric occupation in the Gilf Kebir region of the Eastern Sahara, SW EgyptGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 8 2004Jörg Linstädter Geoarchaeological and chronological evidence from the remote Gilf Kebir Plateau in southwest Egypt suggests a new model for the influence of early and mid-Holocene precipitation regimes on land-use strategies of prehistoric settlers in what is now the center of the largest hyperarid area on earth. We hypothesize that the quantitatively higher, daytime, monsoon summer rainfall characteristic of the early Holocene (9300,5400 14C yr B.P./8400,4300 yr B.C.) resulted in less grass growth on the plateau compared to the winter rains that presumably fell in the cool nights during the terminal phase of the Holocene pluvial (5400,4500 yr B.P./4300,3300 yr B.C.). The unparalleled climatic transition at 5400 yr B.P. (4300 yr B.C.) caused a fundamental environmental change that resulted in different patterns of human behavior, economy, and land use in the canyon-like valleys and on the plains surrounding the plateau. The model emphasizes the crucial impact of seasonal rainfall distribution on cultural landscapes in arid regions and the lower significance of annual precipitation rates, with implications for future numeric climate models. It also serves as an example of how past climate changes have affected human societies. © 2004 Wiley Periodicals, Inc. [source] Low-frequency passive seismic experiments in Abu Dhabi, United Arab Emirates: implications for hydrocarbon detectionGEOPHYSICAL PROSPECTING, Issue 5 2010Mohammed Y. Ali ABSTRACT Low-frequency passive seismic experiments utilizing arrays of 3-component broadband seismometers were conducted over two sites in the emirate of Abu Dhabi in the United Arab Emirates. The experiments were conducted in the vicinity of a producing oilfield and around a dry exploration well to better understand the characteristics and origins of microtremor signals (1,6 Hz), which had been reported as occurring exclusively above several hydrocarbon reservoirs in the region. The results of the experiments revealed that a strong correlation exists between the recorded ambient noise and observed meteorological and anthropogenic noises. In the frequency range of 0.15,0.4 Hz, the dominant feature is a double-frequency microseism peak generated by the non-linear interactions of storm induced surface waves in the Arabian Sea. We observed that the double-frequency microseism displays a high variability in spectral amplitude, with the strongest amplitude occurring when Cyclone Gonu was battering the eastern coast of Oman; this noise was present at both sites and so is not a hydrocarbon indicator. Moreover, this study found that very strong microtremor signals in the frequency range of 2,3 Hz were present in all of the locations surveyed, both within and outside of the reservoir boundary and surrounding the dry exploration well. This microtremor signal has no clear correlation with the microseism signals but significant variations in the characteristics of the signals were observed between daytime and nighttime recording periods that clearly correlate with human activity. High-resolution frequency-wavenumber (f - k) spectral analyses were performed on the recorded data to determine apparent velocities and azimuths of the wavefronts for the microseism and microtremor events. The f - k analyses confirmed that the double-frequency microseism originates from wave activity in the Arabian Sea, while the microtremor events have an azimuth pointing towards the nearest motorways, indicating that they are probably being excited by traffic noise. Results drawn from particle motion studies confirm these observations. The vertical-to-horizontal spectral ratios of the data acquired in both experiments show peaks around 2.5,3 Hz with no dependence on the presence or absence of subsurface hydrocarbons. Therefore, this method should not be used as a direct hydrocarbon indicator in these environments. Furthermore, the analyses provide no direct evidence to indicate that earthquakes are capable of stimulating the hydrocarbon reservoir in a way that could modify the spectral amplitude of the microtremor signal. [source] Human modification of the landscape and surface climate in the next fifty yearsGLOBAL CHANGE BIOLOGY, Issue 5 2002R. S. Defries Abstract Human modification of the landscape potentially affects exchanges of energy and water between the terrestrial biosphere and the atmosphere. This study develops a possible scenario for land cover in the year 2050 based on results from the IMAGE 2 (Integrated Model to Assess the Greenhouse Effect) model, which projects land-cover changes in response to demographic and economic activity. We use the land-cover scenario as a surface boundary condition in a biophysically-based land-surface model coupled to a general circulation model for a 15-years simulation with prescribed sea surface temperature and compare with a control run using current land cover. To assess the sensitivity of climate to anthropogenic land-cover change relative to the sensitivity to decadal-scale interannual variations in vegetation density, we also carry out two additional simulations using observed normalized difference vegetation index (NDVI) from relatively low (1982,83) and high (1989,90) years to describe the seasonal phenology of the vegetation. In the past several centuries, large-scale land-cover change occurred primarily in temperate latitudes through conversion of forests and grassland to highly productive cropland and pasture. Several studies in the literature indicate that past changes in surface climate resulting from this conversion had a cooling effect owing to changes in vegetation morphology (increased albedo). In contrast, this study indicates that future land-cover change, likely to occur predominantly in the tropics and subtropics, has a warming effect governed by physiological rather than morphological mechanisms. The physiological mechanism is to reduce carbon assimilation and consequently latent relative to sensible heat flux resulting in surface temperature increases up to 2 °C and drier hydrologic conditions in locations where land cover was altered in the experiment. In addition, in contrast to an observed decrease in diurnal temperature range (DTR) over land expected with greenhouse warming, results here suggest that future land-cover conversion in tropics could increase the DTR resulting from decreased evaporative cooling during the daytime. For grid cells with altered land cover, the sensitivity of surface temperature to future anthropogenic land-cover change is generally within the range induced by decadal-scale interannual variability in vegetation density in temperate latitudes but up to 1.5 °C warmer in the tropics. [source] Carbon dioxide exchange of a Russian boreal forest after disturbance by wind throwGLOBAL CHANGE BIOLOGY, Issue 3 2002Alexander Knohl Abstract The exchange of carbon dioxide (CO2) between the atmosphere and a forest after disturbance by wind throw in the western Russian taiga was investigated between July and October 1998 using the eddy covariance technique. The research area was a regenerating forest (400 m × 1000 m), in which all trees of the preceding generation were uplifted during a storm in 1996. All deadwood had remained on site after the storm and had not been extracted for commercial purposes. Because of the heterogeneity of the terrain, several micrometeorological quality tests were applied. In addition to the eddy covariance measurements, carbon pools of decaying wood in a chronosequence of three different wind throw areas were analysed and the decay rate of coarse woody debris was derived. During daytime, the average CO2 uptake flux was ,3 µmol m,2s,1, whereas during night-time characterised by a well-mixed atmosphere the rates of release were typically about 6 µmol m,2s,1. Suppression of turbulent fluxes was only observed under conditions with very low friction velocity (u* , 0.08 ms,1). On average, 164 mmol CO2 m,2d,1 was released from the wind throw to the atmosphere, giving a total of 14.9 mol CO2 m,2 (180 g CO2 m,2) released during the 3-month study period. The chronosequence of dead woody debris on three different wind throw areas suggested exponential decay with a decay coefficient of ,0.04 yr,1. From the magnitude of the carbon pools and the decay rate, it is estimated that the decomposition of coarse woody debris accounted for about a third of the total ecosystem respiration at the measurement site. Hence, coarse woody debris had a long-term influence on the net ecosystem exchange of this wind throw area. From the analysis performed in this work, a conclusion is drawn that it is necessary to include into flux networks the ecosystems that are subject to natural disturbances and that have been widely omitted into considerations of the global carbon budget. The half-life time of about 17 years for deadwood in the wind throw suggests a fairly long storage of carbon in the ecosystem, and indicates a very different long-term carbon budget for naturally disturbed vs. commercially managed forests. [source] Net grassland carbon flux over a subambient to superambient CO2 gradientGLOBAL CHANGE BIOLOGY, Issue 7 2001P. C. Mielnick Abstract Increasing atmospheric CO2 concentrations may have a profound effect on the structure and function of plant communities. A previously grazed, central Texas grassland was exposed to a 200-µmol mol,1 to 550 µmol mol,1 CO2 gradient from March to mid-December in 1998 and 1999 using two, 60-m long, polyethylene- covered chambers built directly onto the site. One chamber was operated at subambient CO2 concentrations (200,360 µmol mol,1 daytime) and the other was regulated at superambient concentrations (360,550 µmol mol,1). Continuous CO2 gradients were maintained in each chamber by photosynthesis during the day and respiration at night. Net ecosystem CO2 flux and end-of-year biomass were measured in each of 10, 5-m long sections in each chamber. Net CO2 fluxes were maximal in late May (c. day 150) in 1998 and in late August in 1999 (c. day 240). In both years, fluxes were near zero and similar in both chambers at the beginning and end of the growing season. Average daily CO2 flux in 1998 was 13 g CO2 m,2 day,1 in the subambient chamber and 20 g CO2 m,2 day,1 in the superambient chamber; comparable averages were 15 and 26 g CO2 m,2 day,1 in 1999. Flux was positively and linearly correlated with end-of-year above-ground biomass but flux was not linearly correlated with CO2 concentration; a finding likely to be explained by inherent differences in vegetation. Because C3 plants were the dominant functional group, we adjusted average daily flux in each section by dividing the flux by the average percentage C3 cover. Adjusted fluxes were better correlated with CO2 concentration, although scatter remained. Our results indicate that after accounting for vegetation differences, CO2 flux increased linearly with CO2 concentration. This trend was more evident at subambient than superambient CO2 concentrations. [source] Patient preferences for in-center intense hemodialysisHEMODIALYSIS INTERNATIONAL, Issue 3 2005Nirupama Ramkumar Abstract There is a lack of data on patient preferences for intense hemodialysis (IHD). In this study, we conducted a cross-sectional survey to identify patient preferences and patient-centered barriers for IHD. A questionnaire on preferences and anticipated barriers, anticipated benefits, and quality of life for three in-center IHD schedules (daytime 2 hr six times/week [DHD], nocturnal 8 hr three times/week [ND3], and nocturnal 8 hr six times/week [ND6]) was administered to 100 chronic hemodialysis patients. A majority of patients (68%) were willing to undergo DHD for symptomatic benefits or increase in survival. An increase in energy level (94%) and improvement in sleep (57%) were the most common potential benefits that would justify DHD, but only 19% would undergo DHD for an increase in survival of ,3 years. Only 20% and 7% would consider ND3 and ND6, respectively. The most common reported barriers were inadequate time for self (50%) and family (53%), followed by transportation difficulties (53%). Most patients would undergo DHD for symptomatic or survival benefits, but not ND3 or ND6. Disruption of personal time, however, is an important consideration. Success of DHD program would depend on arrangements for transportation to dialysis unit. [source] Nocturnal nutritional supplementation improves total body protein status of patients with liver cirrhosis: A randomized 12-month trial,HEPATOLOGY, Issue 2 2008Lindsay D. Plank Patients with liver cirrhosis exhibit early onset of gluconeogenesis after short-term fasting. This accelerated metabolic reaction to starvation may underlie their increased protein requirements and muscle depletion. A randomized controlled trial was conducted to test the hypothesis that provision of a late-evening nutritional supplement over a 12-month period would improve body protein stores in patients with cirrhosis. A total of 103 patients (68 male, 35 female; median age 51, range 28,74; Child-Pugh grading: 52A, 31B, 20C) were randomized to receive either daytime (between 0900 and 1900 hours) or nighttime (between 2100 and 0700 hours) supplementary nutrition (710 kcal/day). Primary etiology of liver disease was chronic viral hepatitis (67), alcohol (15), cholestatic (6), and other (15). Total body protein (TBP) was measured by neutron activation analysis at baseline, 3, 6, and 12 months. Total daily energy and protein intakes were assessed at baseline and at 3 months by comprehensive dietary recall. As a percentage of values predicted when well, TBP at baseline was similar for the daytime (85 ± 2[standard error of the mean]%) and nighttime (84 ± 2%) groups. For the nighttime group, significant increases in TBP were measured at 3 (0.38 ± 0.10 kg, P = 0.0004), 6 (0.48 ± 0.13 kg, P = 0.0007), and 12 months (0.53 ± 0.17 kg, P = 0.003) compared to baseline. For the daytime group, no significant changes in TBP were seen. Daily energy and protein intakes at 3 months were higher than at baseline in both groups (P < 0.0001), and these changes did not differ between the groups. Conclusion: Provision of a nighttime feed to patients with cirrhosis results in body protein accretion equivalent to about 2 kg of lean tissue sustained over 12 months. This improved nutritional status may have important implications for the clinical course of these patients. (HEPATOLOGY 2008.) [source] Fatigue in primary biliary cirrhosis is associated with excessive daytime somnolence,HEPATOLOGY, Issue 1 2006Julia L. Newton A significant proportion of patients with primary biliary cirrhosis (PBC) suffer from severe fatigue. The aim of this study was to characterize patterns of daytime sleep in patients with PBC (using both objective and subjective assessment approaches) and to study the association between sleep abnormality and fatigue severity. Fatigue severity was assessed in 48 female subjects with PBC (using a disease-specific quality of life instrument (the PBC-40) and a generic fatigue measure (Fatigue Impact Scale [FIS]) as well as 48 case-matched normal controls. All participants also completed the Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS, which assesses daytime hypersomnolence). Objective sleep assessment was performed using accelerometry over 7 days. Global sleep quality assessed by the PSQI was significantly lower in the PBC group compared to controls (P < .0001). ESS scores were significantly higher in patients with PBC than controls (P = .0001), suggesting significantly greater daytime somnolence in the patients with PBC. Objective sleep assessment confirmed that subjects with PBC were sleeping on average almost twice as long as controls during the daytime. Both degree of daytime somnolence (ESS) and actual daytime sleep activity (accelerometry) correlated strongly with fatigue severity in the patient group (r2 = 0.5, P < .0001 and r2 = 0.2, P < .01, respectively). In conclusion, Sleep abnormality, in the form of excessive daytime somnolence, is present in a significant proportion of patients with PBC, with the degree of daytime somnolence correlating strongly with the degree of fatigue. Existing agents effective at reducing daytime somnolence (such as modafinil) hold potential for the treatment of fatigue in PBC. (HEPATOLOGY 2006;44:91,98.) [source] Impact of the novel antidepressant agomelatine on disturbed sleep,wake cycles in depressed patients,HUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 3 2010Maria-Antonia Quera-Salva Abstract Background Disturbance of sleep,wake cycles is common in major depressive disorder (MDD), usually as insomnia, but also as hypersomnia or reduced daytime alertness. Agomelatine, an MT1 and MT2 receptor agonist and 5-HT2C receptor antagonist, represents a novel approach in MDD, with proven antidepressant efficacy and a positive impact on the sleep,wake cycle. We review the effects of agomelatine 25/50,mg/day on objective and subjective measures of the sleep,wake cycle in MDD. Subjective measures Agomelatine improved all aspects of the sleep,wake cycle from as early as 1 week in randomized trials versus selective serotonin reuptake inhibitors and venlafaxine, particularly getting off to sleep and quality of sleep, with an improvement in daytime alertness. Objective measures Agomelatine's effect on sleep architecture in MDD has been measured by polysomnography (PSG). There were significant improvements in sleep efficiency, slow-wave sleep (SWS), and the distribution of delta activity throughout the night, but no change in amount or latency of rapid eye movement (REM) sleep. Furthermore, the slow-wave sleep was resynchronized to the first sleep cycle of the night. Conclusion Agomelatine, a novel antidepressant, improves disturbed sleep,wake cycles in MDD. The improvement of both nighttime sleep and daytime functioning with agomelatine are promising features of this antidepressant regarding the management of MDD. Copyright © 2010 John Wiley & Sons, Ltd. [source] Water table fluctuations under three riparian land covers, Iowa (USA)HYDROLOGICAL PROCESSES, Issue 18 2007Keith E. Schilling Abstract Water table depth is known to play an important role in nitrogen cycling in riparian zones, but little detailed monitoring of water table fluctuations has been reported. In this study, results of high-resolution water table monitoring under three common riparian land covers (forest, cool season grass, corn) were analysed to gain a better understanding of the relation of vegetation cover to water table depth. Three riparian wells located at the Neal Smith National Wildlife Refuge in Jasper County, Iowa, were instrumented with data loggers to record hourly water table behaviour from July to December 2004. Water table depth under the forest showed a diurnal pattern of rising and falling water levels, whereas the grass and corn exhibited a stepped pattern of greater drawdown during the day and less drainage at night. Clear daytime and night-time water table signals were related to daily plant water demands and lateral groundwater flow. Using two estimates of specific yield, hourly and daily ET rates were estimated to be higher under the forest cover than the grass and corn, with peak ET rates in July ranging from 5·02 to 6·32 mm day,1 for forest and from 1·81 to 4·13 mm day,1 for corn and grass. Following plant senescence in October, water table declines were associated with lateral flow to Walnut Creek. The results from this study suggest that consideration should be given to monitoring water table behaviour more frequently to capture daily and seasonal patterns related to riparian vegetation type. Copyright © 2007 John Wiley & Sons, Ltd. 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