Satellite imagery: a way to monitor water quality for the future?

Monitoring water at high spatial and temporal resolutions is important for maintaining water quality because the cost of pollution remediation is often higher than the cost of early prevention or intervention. In recent decades, the availability and affordability of satellite images have regularly increased, thus supporting higher-frequency and lower-cost alternative methods for monitoring water quality. The core step in satellite remote sensing detection is inverse modeling, which is used to calibrate model parameters and enhance the similarity between the model and the real system being simulated. The reflectance values measured at water quality stations are extracted from atmosphere-corrected satellite imagery for analysis. However, various external environmental, hydrological, and meteorological factors affect the evaluation results, and the results obtained with different parameters can vary. This literature review shows that nonpoint-source pollution caused by stormwater runoff can also be monitored using satellite imagery. To improve the accuracy of satellite-based water quality prediction, the temporal resolution of field measurements can be increased, thus better considering the influence of seasonality. Then, the atmospheric correction module can be improved by using available atmospheric water content products. Moreover, because water surface ripples affect reflectance, wind speed and direction should be considered when comparing water quality scenes.

Using Landsat 8 imagery for remote monitoring of total phosphorus as a water quality parameter of irrigation ponds in Taiwan.

Monitoring water body quality parameters with high spatial and temporal resolutions is crucial because mitigation of pollution is usually costlier than early prevention/intervention. The existing monitoring methods for irrigation ponds in Taoyuan, Taiwan, are based on field measurements that have low spatial and temporal resolutions. In this study, using Landsat 8 satellite imagery, a multiple regression-derived relationship between the satellite band reflectance and the concentration of total phosphorus (TP) was established. The satellite imagery was atmospherically corrected with ACOLITE based on shortwave infrared (SWIR) bands. This method was used to select predictor variables in the multiple regression-derived equation based on forward selection of variables using a p value and variation inflation factor (VIF) threshold. The derived equation yielded a coefficient of determination (R2) of 0.67. The near-infrared band (band 5) was found to be most significant. The Landsat 8 imagery retrieved for two of the three pond studies included only a few pixels from the ponds because parts of the pond surfaces are covered by floating photovoltaic power plants. The TP concentrations resulting from the derived equation indicate the feasibility of using satellite remote sensing methods to monitor the water quality. The derived relationships are potentially applicable to extend the availability of temporal and spatial water quality data for these irrigation ponds.

Dynamic Modeling and Experimental Validation of an Impact-Driven Piezoelectric Energy Harvester in Magnetic Field.

In this study, an impact-driven piezoelectric energy harvester (PEH) in magnetic field is presented. The PEH consists of a piezoelectric cantilever beam and plural magnets. At its initial status, the beam tip magnet is attracted by a second magnet. The second magnet is moved away by hand and then the beam tip magnet moves to a third magnet by the guidance of the magnetic fields. The impact occurs when the beam motion is stopped by the third magnet. The impact between magnets produces an impact energy and causes a transient beam vibration. The electric energy is generated by the piezoelectric effect. Based on the energy principle, a multi-DOF (multi-degree of freedom) mathematical model was developed to calculate the displacements, velocities, and voltage outputs of the PEH. A prototype of the PEH was fabricated. The voltages outputs of the beam were monitored by an oscilloscope. The maximum generated energy was about 0.4045 mJ for a single impact. A comparison between numerical and experimental results was presented in detail. It showed that the predictions based on the model agree with the experimental measurements. The PEH was connected to a diode bridge rectifier and a storage capacitor. The charges generated by the piezoelectric beam were stored in the capacitor by ten impacts. The experiments showed that the energy stored in the capacitor can light up the LED.

Prevalence and clinical correlates of flunitrazepam-related complex sleep behaviors.

AIM: Complex sleep behaviors (CSB) are often associated with the use of hypnotic drugs. This study investigated the prevalence and correlates of CSB among psychiatric patients who were given flunitrazepam. METHODS: From June 2011 to May 2012, a total of 268 psychiatric outpatients who had received flunitrazepam for at least 3 months were enrolled. Data on occurrence of CSB, demographic characteristics, flunitrazepam dosage and duration of use, psychiatric diagnoses, physical illnesses, and alcohol use were collected. Logistic regression analysis was used to examine the clinical correlates of CSB. RESULTS: Sixty-six participants (24.6%) reported experiencing CSB. Logistic regression analysis showed that a high dosage (>2 mg/day) of flunitrazepam (odds ratio [OR] = 1.941, 95% confidence interval [CI] = 1.090-3.455, P = 0.024) and alcohol use (OR = 1.948, 95%CI = 1.023-3.709, P = 0.042) were significantly associated with the occurrence of CSB. Sex, age, duration of flunitrazepam use, psychiatric diagnoses, and physical illnesses were not significantly associated with the occurrence of CSB. CONCLUSION: CSB among flunitrazepam users should be monitored routinely, especially among those receiving a high dosage who also consume alcohol.

Correlates of dependence and beliefs about the use of hypnotics among zolpidem and zopiclone users.

BACKGROUND: Zolpidem and zopiclone are the two most commonly prescribed Z-drugs approved to treat insomnia. OBJECTIVES: To examine the demographic and clinical correlates of dependence and beliefs about hypnotic use among long-term zolpidem and zopiclone users in psychiatric treatment for insomnia. METHODS: A total of 392 psychiatric outpatients who received zolpidem or zopiclone treatment for at least 3 months for insomnia were studied. Participants' severity of hypnotic dependence and beliefs about the use of hypnotics to treat sleep problems were assessed. The correlation of dependence and beliefs about zolpidem and zopiclone treatment with demographic characteristics, hypnotic-using behaviors, co-use of addictive substances, and depressive symptoms were analyzed using multiple regression analysis models. RESULTS: Zolpidem users reported more severe dependence and a lower level of necessity regarding the use of hypnotics than zopiclone users did. High equivalent doses of hypnotics and long duration of use were significantly associated with severe dependence and a low level of necessity. Severe depressive symptoms were signiciantly associated with severe dependence, a low level of necessity, and a low level of concern. Educational level was also associated with the levels of concern and necessity. Conclusions/Importance: There were differences in the level of dependence and belief about hypnotic use between zolpidem and zopiclone users. The correlates of dependence and belief identified in this study can serve as the basis for prevention and intervention programs.

Severity of alprazolam dependence and associated features among long-term alprazolam users from psychiatric outpatient clinics in Taiwan.

BACKGROUND/PURPOSE: The aim of this study was to examine the correlations between the severity of alprazolam dependence and socio-demographic characteristics, the characteristics of alprazolam use, psychiatric comorbidity, and beliefs toward alprazolam use among long-term alprazolam users in Taiwan. METHODS: A total of 148 long-term alprazolam users participated in this study. The Chinese version of the Severity of Dependence Scale was used to assess participants' severity of alprazolam dependence in the preceding month. Their socio-demographic characteristics, family function characteristics, dosage of prescribed alprazolam, duration of alprazolam use, alcohol use pattern, pain reliever and cigarette use pattern, severity of depressive symptoms, psychiatric diagnosis, and belief toward alprazolam use were investigated. RESULTS: The results of multiple regression analysis indicated that a longer duration of alprazolam use, severe depressive symptoms, a high level of belief in the necessity of alprazolam treatment, and a high level of concern about the potential adverse consequences of alprazolam use were significantly associated with more severe alprazolam dependence. CONCLUSION: Doctors should closely monitor the severity of alprazolam dependence among long-term users, especially patients' levels of depression, beliefs in the necessity of alprazolam treatment, and their concerns over the adverse consequences of continued treatment with alprazolam.

Clinical correlates of zolpidem-associated complex sleep-related behaviors: age effect.

OBJECTIVE: Complex sleep-related behaviors (CSBs) are often associated with hypnotic use, especially zolpidem. The age effect on the occurrence of CSBs has not been adequately investigated. This study aimed to investigate and compare the clinical correlates of CSBs between adult and elderly subjects who were taking zolpidem. METHOD: A total of 253 adults (aged 20-55 years) and 64 elderly subjects (aged ≥ 65 years) who were administered zolpidem for at least 3 months were enrolled from psychiatric outpatient clinics from June 2011 to May 2012. The sociodemographic characteristics of the participants, the dose of zolpidem, and the occurrence of CSBs were collected. Logistic regression analysis was used to examine the clinical correlates of CSBs. RESULTS: In total, there were 62 members of the adult group (24.5%) and 11 elderly subjects (17.2%) with CSBs; however, the difference did not reach statistical significance. Logistic regression analysis showed that there was a main effect of zolpidem dose (≥ 10 mg; OR = 2.82, P = .038) and alcohol use (OR = 2.05, P = .026), but not sex or age group. There were interactive effects between age group and zolpidem dose (P = .043), indicating that a higher dose of zolpidem was associated with CSBs only in the adult group and not in the elderly group. Adults with CSBs used a higher dose of zolpidem than adults without (mean ± SD: 15.4 ± 6.8 mg vs 11.3 ± 5.7 mg), whereas elderly patients with CSBs did not use a higher dose of zolpidem than those without (12.2 ± 5.4 mg vs 11.9 ± 7.0 mg). CONCLUSIONS: A higher dose of zolpidem was correlated with CSBs only in the adult group and not in the elderly group. Future studies investigating the factors, other than dose, related to CSBs in the elderly will be performed.

Effects of paliperidone extended release on the symptoms and functioning of schizophrenia.

BACKGROUND: We aimed to explore relations between symptomatic remission and functionality evaluation in schizophrenia patients treated with paliperidone extended-release (ER), as seen in a normal day-to-day practice, using flexible dosing regimens of paliperidone ER. We explored symptomatic remission rate in patients treated with flexibly dosed paliperidone ER by 8 items of Positive and Negative Syndrome Scale (PANSS) and change of Personal and Social Performance (PSP) scale. METHOD: This was a 12-week multicenter, open-label, prospective clinical study conducted in in-patient and out-patient populations. Flexible dosing in the range 3-12 mg/day was used throughout the study. All subjects attended clinic visits on weeks 0, 4, 8, and 12 as usual clinical practice for the 12-week observation period. Data were summarized with respect to demographic and baseline characteristics, efficacy measurement with PANSS scale, PSP, and social functioning score, and safety observations. Descriptive statistics were performed to identify the retention rate at each visit as well as the symptomatic remission rate. Summary statistics of average doses the subjects received were based on all subjects participating in the study. RESULTS: A total of 480 patients were enrolled. Among them, 426 patients (88.8%) had evaluation at week 4 and 350 (72.9%) completed the 12-week evaluation. Patients with at least moderate severity of schizophrenia were evaluated as "mild" or better on PANSS scale by all 8 items after 12 weeks of treatment with paliperidone ER. There was significant improvement in patients' functionality as measured by PSP improvement and score changes. Concerning the other efficacy parameters, PANSS total scale, PSP total scale, and social functioning total scale at the end of study all indicated statistically significant improvement by comparison with baseline. The safety profile also demonstrated that paliperidone ER was well-tolerated without clinically significant changes after treatment administration. CONCLUSIONS: Although the short-term nature of this study may limit the potential for assessing improvements in function, it is noteworthy that in the present short-term study significant improvements in patient personal and social functioning with paliperidone ER treatment were observed, as assessed by PSP scale. TRIAL REGISTRATION: Clinical Trials. PAL-TWN-MA3.