A projection of benefits due to fecal occult blood test for colorectal cancer

Objectives: A prospective study to estimate benefits due to fecal occult blood tests for colorectal cancer are carried out for both males and females, under different screening frequencies. Methods: We apply the statistical method developed by Wu et al. (2007) [1] using the Minnesota colorectal cancer study group data, to make Bayesian inference for the lead time, the time of diagnosis advanced by screening for both male and female participants in a periodic screening program. The lead time is distributed as a mixture of a point mass at zero and a piecewise continuous distribution. The two parts of the mixture correspond to two aspects of the screening: the probability of no benefit, or the percentage of interval cases; and the probability distribution of the early diagnosis time. We present estimates of these two measures for males and females by simulation studies using the Minnesota study group data. We also provide the mean, mode, variance, and density curve of the program's lead time by gender. This may provide policy makers important information on the effectiveness of the FOBT screening in colorectal cancer early detection. Results: The mean lead time increases as the screening time interval decreases for both males and females. The standard error of the lead time also increases as the screening time interval decreases for both genders. Females seem get more benefit than males, in that females usually have a longer lead time than males if both take the test at the same time interval and the lead time mode for females is greater than that of males in the same screening time interval. Conclusion: According to the predictive estimation of the lead time distribution, to guarantee a 90% chance of early detection, it seems necessary for the males to take the fecal occult blood test every 9 months, while the females can take it annually.     

Response probability and response time: a straight line, the Tagging/Retagging interpretation of short term memory, an operational definition of meaningfulness and short term memory time decay and search time

The functional relationship between correct response probability and response time is investigated in data sets from Rubin, Hinton and Wenzel, J Exp Psychol Learn Mem Cogn 25:1161–1176, 1999 and Anderson, J Exp Psychol [Hum Learn] 7:326–343, 1981. The two measures are linearly related through stimulus presentation lags from 0 to 594 s in the former experiment and for repeated learning of words in the latter. The Tagging/Retagging interpretation of short term memory is introduced to explain this linear relationship. At stimulus presentation the words are tagged. This tagging level drops slowly with time. When a probe word is reintroduced the tagging level has to increase for the word to be properly identified leading to a delay in response time. The tagging time is related to the meaningfulness of the words used—the more meaningful the word the longer the tagging time. After stimulus presentation the tagging level drops in a logarithmic fashion to 50% after 10 s and to 20% after 240 s. The incorrect recall and recognition times saturate in the Rubin et al. data set (they are not linear for large time lags), suggesting a limited time to search the short term memory structure: the search time for recall of unusual words is 1.7 s. For recognition of nonsense words the corresponding time is about 0.4 s, similar to the 0.243 s found in Cavanagh (1972).     

Studies on the mass and temperature dependence of lyoluminescence intensity of microcrystalline powder of KCl

The temperature and mass dependence of lyoluminescence intensity of γ‐irradiated colored potassium chloride powder have been studied using a photomultiplier tube connected to an x–y recorder. The peak lyoluminescence intensity increases with increasing amount of solute added up to 50 mg and then tends to saturate. The lyoluminescence (LL) glow curves with mass of KCl microcrystals show that initially the LL intensity increases with time and then decreases exponentially with time. The decay time consists of two components for all the masses. The dependence of decay time, especially the longer component on mass, has been investigated. The temperature dependence of LL intensity shows that initially the peak LL intensity increases with temperature up to 60°C, and then decreases with further increase in temperature. The decay time tends to decrease with increasing temperature. An explanation for the experimental results has been attempted. Copyright © 2010 John Wiley & Sons, Ltd.     

An application of optimal diving models to diving behaviour of Brünnich's guillemots

Although theoretical models predict that the quality of foraging patches has little effect on optimal dive time with increasing depth, many empirical studies show that dive time at a given depth may vary. We developed a model that incorporated patch quality as a parameter of energy intake as a nonlinear function of time, and applied it to the diving behaviour of Brünnich's guillemots, Uria lomvia. The model indicated that optimal dive time can vary widely depending on the parameter. It also explained the convergence of observed dive times with travel time. Assuming the birds dived optimally, this parameter can be estimated from travel time and dive time for each dive. Foraging patches with larger estimated parameter values were favoured by the birds, suggesting that the parameter indicated patch quality. We used this parameter to test an optimal patch use model in divers. The results indicate that Brünnich's guillemots adjust their diving behaviour adaptively depending on patch quality, and that the optimal diving model is valid for prediction of observed dive patterns if patch quality is incorporated appropriately. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.     

蝴蝶兰红花系品种杂交种子形态及胚培养研究

对21个蝴蝶兰自交或杂交组合的种子形态进行观察和无菌培养,结果表明,蝴蝶兰不同组合的种子形态有一定差异,平均种子长、宽及种胚长、宽分别为0.292±0.025 mm、0.073±0.003 mm及0.151±0.009 mm、0.069±0.003 mm。种子萌发率及萌发所需时间因组合而异,平均萌发率为72.4%,原球茎及第一片叶出现所需时间分别为22±3 d、78±6 d,杂交组合启动萌发早、萌发率高。种子启动萌发所需时间、萌发率与果实、种子大小相关不显著,而种子启动萌发所需时间与种胚长、宽呈极显著负线性相关,表明种胚越大,萌发越快。     

In vitro expression of partial resistance toPhytophthora palmivora by shoot cultures of papaya

Shoot apices ofCarica papaya were multiplied in vitro on solidified nutrient media supplemented with -naphthyl-acetic acid and 6-benzylaminopurine. The micropropagated shoots were inoculated in vitro, through a stem wound, with a sporangial suspension (1.2×10⁴ sporangia ml^-1) ofPhytophthora palmivora. The symptoms exhibited by the shoots in vitro were similar to those described previously for infection of the whole plant in the field. The time taken for the host tissue to become brown and to wilt and the time to sporulation of the pathogen were all recorded for each shoot of four varieties of papaya challenged with each of ten isolates ofP. palmivora. Significant differences were observed between host-pathogen combinations for these variables and host-specificity was detected amongst the isolates ofP. palmivora. The time taken for the shoot to wilt was positively correlated with the time to sporulation of the isolated but both these variables were negatively correlated with the time to browning of the shoot. In vitro selection for disease resistance will be useful during breeding programmes involving papaya genotypes which are maintained through clonal propagation.     

The Impact of Travel Time on Geographic Distribution of Dialysis Patients

Backgrounds

The geographic disparity of prevalence rates among dialysis patients is unclear. We evaluate the association between travel time to dialysis facilities and prevalence rates of dialysis patients living in 1,867 census areas of Hiroshima, Japan. Furthermore, we study the effects of geographic features (mainland or island) on the prevalence rates and assess if these effects modify the association between travel time and prevalence.

Methods

The study subjects were all 7,374 people that were certified as the “renal disabled” by local governments in 2011. The travel time from each patient to the nearest available dialysis facility was calculated by incorporating both travel time and the capacity of all 98 facilities. The effect of travel time on the age- and sex-adjusted standard prevalence rate (SPR) and 95% confidence intervals (CIs) at each census area was evaluated in two-level Poisson regression models with 1,867 census areas (level 1) nested within 35 towns or cities (level 2). The results were adjusted for area-based parameters of socioeconomic status, urbanity, and land type. Furthermore, the SPR of dialysis patients was calculated in each specific subgroup of population for travel time, land type, and combination of land type and travel time.

Results

In the regression analysis, SPR decreased by 5.2% (95% CI: −7.9–−2.3) per 10-min increase in travel time even after adjusting for potential confounders. The effect of travel time on prevalence was different in the mainland and island groups. There was no travel time-dependent SPR disparity on the islands. The SPR among remote residents (>30 min from facilities) in the mainland was lower (0.77, 95% CI: 0.71–0.85) than that of closer residents (≤30 min; 0.95, 95% CI: 0.92–0.97).

Conclusions

The prevalence of dialysis patients was lower among remote residents. Geographic difficulties for commuting seem to decrease the prevalence rate.     

Kinetic Modelling for the Assay of Nortriptyline Hydrochloride Using Potassium Permanganate as Oxidant

Kinetic methods for accurate determination of nortriptyline hydrochloride have been described. The methods are based on the oxidation of nortriptyline hydrochloride with KMnO₄ in acidic and basic media. In acidic medium, the decrease in absorbance at 525.5 nm and in basic medium, the increase in absorbance at 608.5 nm were measured as a function of time. The variables affecting the reactions were carefully investigated and optimised. Kinetic models such as initial rate, rate constant, variable time and fixed time were employed to construct the calibration curves. The initial rate and fixed time methods were selected for quantification of nortriptyline hydrochloride. In acidic medium, the calibration curves showed a linear response over the concentration range 10–50 μg mL⁻¹ for initial rate and 10–60 μg mL⁻¹ for fixed time method (2 min). In basic medium, the calibration graphs were linear over the concentration range 10–100 μg mL⁻¹ for initial rate and fixed time methods (4 min). In acidic medium, the limits of detection for initial rate and fixed time methods (2 min) were 1.02 and 3.26 μg mL⁻¹, respectively. In basic medium, the limits of detection were found to be 1.67 and 1.55 μg mL⁻¹ for initial rate and fixed time methods (4 min), respectively. The initial rate and fixed time methods have been successfully applied to the determination of nortriptyline hydrochloride in commercial dosage form. Statistical comparison of the results of the proposed methods with those of reference method exhibited excellent agreement and there is no significant difference between the compared methods in terms of accuracy and precision.KEY WORDS: dosage forms, fixed time method, initial rate method, nortriptyline, potassium permanganate     

Effect of noise and filtering on largest Lyapunov exponent of time series associated with human walking

This study aimed to determine the effect of added noise, filtering and time series length on the largest Lyapunov exponent (LyE) value calculated for time series obtained from a passive dynamic walker. The simplest passive dynamic walker model comprising of two massless legs connected by a frictionless hinge joint at the hip was adopted to generate walking time series. The generated time series was used to construct a state space with the embedding dimension of 3 and time delay of 100 samples. The LyE was calculated as the exponential rate of divergence of neighboring trajectories of the state space using Rosenstein’s algorithm. To determine the effect of noise on LyE values, seven levels of Gaussian white noise (SNR = 55–25 dB with 5 dB steps) were added to the time series. In addition, the filtering was performed using a range of cutoff frequencies from 3 Hz to 19 Hz with 2 Hz steps. The LyE was calculated for both noise-free and noisy time series with different lengths of 6, 50, 100 and 150 strides. Results demonstrated a high percent error in the presence of noise for LyE. Therefore, these observations suggest that Rosenstein’s algorithm might not perform well in the presence of added experimental noise. Furthermore, findings indicated that at least 50 walking strides are required to calculate LyE to account for the effect of noise. Finally, observations support that a conservative filtering of the time series with a high cutoff frequency might be more appropriate prior to calculating LyE.     

Factors Affecting the Timing of Signal Detection of Adverse Drug Reactions

We investigated factors affecting the timing of signal detection by comparing variations in reporting time of known and unknown ADRs after initial drug release in the USA. Data on adverse event reactions (AERs) submitted to U.S. FDA was used. Six ADRs associated with 6 drugs (rosuvastatin, aripiprazole, teriparatide, telithromycin, exenatide, varenicline) were investigated: Changes in the proportional reporting ratio, reporting odds ratio, and information component as indexes of signal detection were followed every 3 months after each drugs release, and the time for detection of signals was investigated. The time for the detection of signal to be detected after drug release in the USA was 2–10 months for known ADRs and 19–44 months for unknown ones. The median lag time for known and unknown ADRs was 99.0–122.5 days and 185.5–306.0 days, respectively. When the FDA released advisory information on rare but potentially serious health risks of an unknown ADR, the time lag to report from the onset of ADRs to the FDA was shorter. This study suggested that one factor affecting signal detection time is whether an ADR was known or unknown at release.     

Response of Photosynthesis Models to Light Limitation

An investigation into the effect of time step on a common photosynthesis algorithm reveals that the predicted phytoplankton production and biomass depend strongly on the length of the time step. This time step dependence is due to the assumption that a light limitation factor derived from integrating the irradiance over the time step is equivalent to the integrated light limitation factor over the time step. This subtle inaccuracy in defining the factor for light limited phytoplankton production produces a substantial difference in the biomass estimates derived from the two models. To illustrate the difference, the light limitation factor integrated over the time step is implemented in the one dimensional water quality model DYRESM-WQ. The new version of DYRESM-WQ is used to simulate chlorophyll N concentrations in Prospect Reservoir, New South Wales. These results are compared to concentrations predicted using the original algorithm. The comparison shows that the new algorithm for phytoplankton production is relatively insensitive to time step, which decreases the difficulty of calibrating the model for chlorophyll a.     

Comparison of dose distribution in IMRT and RapidArc technique in prostate radiotherapy

AimThe aim was to provide a dosimetric comparison between IMRT and RapidArc treatment plans with RPI index with simultaneous comparison of the treatment delivery time.BackgroundIMRT and RapidArc provide highly conformal dose distribution with good sparing of normal tissues. However, a complex spatial dosimetry of IMRT and RapidArc plans hampers the evaluation and comparison between plans calculated for the two modalities. RPI was used in this paper for treatment plan comparisons. The duration of the therapeutic session in RapidArc is reported to be shorter in comparison to therapeutic time of the other dynamic techniques. For this reasons, total treatment delivery time in both techniques was compared and discussed.Materials and methods15 patients with prostate carcinoma were randomly selected for the analysis. Two competitive treatment plans using respectively the IMRT and RapidArc techniques were computed for each patient in Eclipse planning system v. 8.6.15. RPIwin^® application was used for RPI calculations for each treatment plan.Additionally, total treatment time was compared between IMRT and RapidArc plans. Total treatment time was a sum of monitor units (MU) for each treated field.ResultsThe mean values of the RPI indices were insignificantly higher for IMRT plans in comparison to rotational therapy. Comparison of the mean numbers of monitor units confirmed that the use of rotational technique instead of conventional static field IMRT can significantly reduce the treatment time.ConclusionAnalysis presented in this paper, demonstrated that RapidArc can compete with the IMRT technique in the field of treatment plan dosimetry reducing the time required for dose delivery.     

Correlation between time of flowering and phenotypic plasticity in Arabidopsis thaliana (Brassicaceae)

We observed substantial variation in the time of flowering among 13 populations of Arabidopsis thaliana (Brassicaceae) from an extensive latitudinal range when grown under uniform experimental conditions. The later the onset of flowering, the greater was potential reproduction. Later flowering plants also had greater plasticity in a host of morphological and physiological traits measured in nutrient-rich vs. nutrient-poor test environments. This relationship between flowering time and overall plasticity was only apparent for traits measured at the time of seed production, not at the time of flowering or earlier. At the time of seed production in this short-lived annual, the regression of a multivariate measure of overall plasticity on the time of flowering was linear and highly significant (r² = 0.90, P < 0.0001). These correlations among time of flowering, reproductive fitness, and plasticity support the idea that selection for late-flowering genotypes would select concomitantly for greater plasticity.     

采收期对‘红心’番石榴品质和耐贮性的影响

以福建漳州栽培的‘红心’番石榴(Psidium guajava ‘Hongxin’)为材料,探究不同采收期对其果实采后耐贮性和品质的影响。实验分盛花期后95 d (采收期Ⅰ)、105 d (采收期Ⅱ)和115 d (采收期Ⅲ) 3个时段进行采收,采后果实在常温(25±1℃) 和相对湿度85%条件下贮藏,贮藏期间测定番石榴果实商品率、失重率、呼吸强度、相对电导率、色调角、硬度、可溶性固形物、可滴定酸、维生素C和总糖含量变化。结果表明,‘红心’番石榴果实采后软化迅速,颜色由绿转黄较快;随着采后贮藏时间的延长,番石榴果实的商品率、硬度、色调角、可滴定酸、维生素C和总糖的含量降低,而果实失重率、细胞膜相对透性增加;采收期Ⅰ较采收期Ⅱ、Ⅲ的耐贮性强。因此,对于‘红心’番石榴果实,考虑贮运期长,适宜在采收期Ⅰ采收;其他两个采收期可在产地销售。     

中国西南季风常绿阔叶林不同恢复阶段凋落物动态分析

为探索季风常绿阔叶林不同恢复阶段群落凋落物产量及其动态变化规律,于云南普洱地区通过设置凋落物承接网并定期收集网内的凋落物,对中国西南季风常绿阔叶林区不同恢复阶段群落凋落物产量及其动态变化进行研究。结果表明:(1)不同恢复阶段季风常绿阔叶林年凋落物总量在8 133.1~8 798.3kg/hm2之间,年凋落物总量大小关系为恢复30年群落老龄林群落恢复40年群落。其中叶凋落量最高,其次为枝凋落量,两者贡献量超过总凋落量的3/4。(2)季风常绿阔叶林不同恢复阶段群落中凋落物随时间的动态变化趋势大致相同,2月份达到高峰值,随后逐渐减少,在9月份降至最低,随后又有所升高,为单峰或多峰曲线;在不同凋落物组分凋落量时间动态上,不同恢复阶段群落叶凋落量随月份变化均为单峰曲线;枝凋落量在恢复群落中为单峰曲线,而在老龄林中则为多峰曲线;皮凋落量随月份的变化在恢复30年及老龄林群落间均为单峰曲线,但在恢复40年群落中为平缓曲线,月份间变化不大;繁殖体凋落物在恢复30年及老龄林群落间均为多峰曲线,但在恢复40年群落中为单峰曲线;半分解物凋落量在恢复30年及老龄林群落中随月份呈单峰曲线,在恢复40年群落中则为多峰曲线。(3)在短刺栲、刺栲和红木荷3种优势物种中,短刺栲叶片年凋落量在所有群落中均最大(分别占恢复30年群落的53.93%、恢复40年群落的47.83%、老龄林的28.32%),红木荷次之(分别占恢复30年群落的8.45%、恢复40年群落的10.71%、老龄林的31.69%),刺栲最少(分别占恢复30年群落的6.1%、恢复40年群落的7.53%、老龄林的6.36%)。短刺栲叶凋落量随月份的变化在恢复群落中呈单峰曲线,而在老龄林中则呈现多峰曲线;红木荷在3种群落中则均为单峰曲线;刺栲则是在恢复30年及老龄林中呈单峰曲线,而在恢复40年群落中呈多峰曲线。     

Time motion study to evaluate the impact of flattening filter free beam on overall treatment time for frameless intracranial radiosurgery using Varian TrueBeam® linear accelerator

BackgroundThe aim was to study the impact of the flattening filter free (FFF) beam on overall treatment time for frameless intracranial radiosurgery using TrueBeam^® LINAC.The development of frameless stereotactic radiosurgery (SRS) is possible due to the incorporation of image guidance in the delivery of treatment. It is important to analyze the cost and benefits of FFF beams for treating SRS by understanding the impact of FFF beams in reducing the treatment time.Materials and methodsDynamic conformal arc (DCA ) and volumetric arc therapy (VMAT) plans were generated using 6 MV with a flattening filter (FF) and FFF beams. Overall treatment time was divided into beam on time (BOT) and beam off time (BFT). Percentage beam on time reduction (PBOTR) and Percentage total time reduction (PTTR) factors were defined for the comparison.ResultsBOT reduction was observed to be significant for higher dose per fraction but subjected to the treatment technique and modulation differences. PBOTR values are much higher than PTTR values. The 39.9% of PBOTR resulted in only 8% PTTR for DCA and 65.3% resulted in 15.9% PTTR for VMAT.ConclusionMajor BFT was utilized for imaging and verification. FFF beam significantly reduced the beam on time and was found to be most effective if the fractional dose was as high as that for SRS. Newly defined PBOTR and PTTR factors are very useful indicators to evaluate the efficacy of FFF beams in terms of time reduction.     

Investigations on decomposition of foliage of woody species using a perfusion method

The time for half of the total oxidizable carbon to be converted into CO₂ and other gaseous products (t_1/2) was studied for five tree species used in agroforestry. The study was conducted in a perfusion system with continuous aeration, and moisture content maintained at field capacity. This method was found to be suitable for studies of the initial stages of tree foliage decomposition. The overall rate was in the decreasing order: Leucaena>Calliandra>Gliricidia>Prosopis>Cassia. Decomposition started rapidly and then decreased rapidly for 2 to 3 weeks followed by a gradual decrease which continued for the remainder of the time.The time for 50 per cent of total oxidizable carbon to decompose was about 19 days for Leucaena, 30 days for Calliandra and Gliricidia, while Prosopis and Cassia took more than 30 days. Leucaena released the largest quantity of total N into the perfusing solution while Cassia gave the lowest amount.     

Activity patterns of a troop of Japanese monkeys (Macaca fuscata yakui) on Yakushima Island,Japan

Activity patterns of Japanese monkeys (Macaca fuscata) were observed for 240 hr from August to December 1976 on the western slope of Mt. Kuniwari, Yakushima Island, Japan. Activity patterns and the time budget of a habituated wild troop which consisted of 47 animals in August 1976, were studied quantitatively by using the scan-sampling method at 15-min intervals. Six thousand seven hundred and six animals were recorded in 959 scans during the study period and the mean number of animals seen per scan was 7.0. The time budget established for different categories of activity was as follows: inactive—20.9%; moving—22.8%; feeding—23.5%; social grooming—27.9%; self-grooming—1.2%; and other activities—3.7%. Adult males spent less time in feeding and more time in resting or being inactive than females or juveniles. The daily activity patterns were highly variable with respect to time. Intraspecific variations were examined between troops in several regions of Japan and it was noted that the percentages of time devoted to feeding were similar in all areas. Inter-species variations in the activity budgets of several species of primates were also examined. The percentage of time spent in social grooming by Japanese monkeys is exceptionally high compared to that recorded in other species.