Investigating the link between $$\hbox {PM}_{2.5}$$ and atmospheric profile variables via penalized functional quantile regression

Fine particulate matter (\(\hbox {PM}_{2.5}\)) events negatively affect the health of numerous persons globally each year. Previous works have described the association between air pollution and surface-level meteorological conditions; however, there has been less focus on the task of linking air pollution events with meteorological conditions at higher levels of the atmosphere. Working within the functional data framework, we develop a penalized functional quantile regression (PFQR) procedure to model conditional quantiles of a continuous response based on a functional covariate, with the ability to penalize selected derivatives of the estimated coefficient function. Our aim is to investigate the relationship between atmospheric profile variables (APVs), assumed to be functional, and key quantiles of the conditional distribution of surface-level \(\hbox {PM}_{2.5}\). Via a simulation study, we find that the performance of our PFQR procedure compares favorably to other related approaches. We conclude with an analysis of \(\hbox {PM}_{2.5}\) data at two Southeastern US locations, Columbia, SC and Tampa, FL, where we estimate the coefficient functions for the APVs corresponding to both ‘typical’ and ‘high’ \(\hbox {PM}_{2.5}\) events. As we believe that the true coefficient functions are smooth and may be exactly zero over subsets of their domains, we impose penalties on the 0th and 2nd derivatives. Our analysis indicates that the corresponding atmospheric conditions differ between the two locations, and that the conditions differ seasonally within location.     

Analysis and prediction of $$\mathrm{PM}_{10}$$ concentration levels in Tunisia using statistical learning approaches

Over the past years, the health impact of airborne particulate matter \(\mathrm{PM}_{10}\) has become a very topical subject. Thereby, a lot of research effort in the environmental sciences goes towards the modeling and the prediction of ambient \(\mathrm{PM}_{10}\) concentrations. In this paper, we are interested in the statistical classification of the daily mean \(\mathrm{PM}_{10}\) concentration in Tunisia according to the authority regulation. We consider two monitoring stations: a big industrial station and a traffic station. The main goal of this work is to determine the pertinent predictors of \(\mathrm{PM}_{10}\) concentration within a nonlinear multiclass framework. To do this, we used two popular statistical learning methods; the support vector machines (SVM) and the random forests (RF). The statistical results obtained on the real datasets, show that RF outperform SVM for the purpose of variable selection even with a reduced number of observations compared to the number of explicative variables. It was also demonstrated that the \(\mathrm{PM}_{10}\) concentration measured yesterday is the most relevant predictor of its present-day value. Moreover, we found that the more delayed values of \(\mathrm{PM}_{10}\) concentration may be crucial to get an accurate prediction.     

A statistical model to forecast the profile of the index structure constant $${C_N^2}$$

A statistical study was performed over 145 profiles of meteorological balloons, equipped with microthermal sensors, from the ground to the midstratosphere. This study put into evidence the lognormal distribution of the fluctuations of the structure constant of temperature, the fluctuations of the buoyancy force and the vertical shear of the horizontal wind speed. We show that these quantities, computed over a large scale (100 m), are correlated up to the midstratosphere. A model is adjusted to estimate the optical turbulence strength from the macroscopic meteorological parameters. The model performances, to estimate and forecast the strength and the altitude of the optical turbulent layers, are quantified and compared with other already defined models. This model was shown to have the best performances and put into evidence a new relation to describe the turbulence on a large scale.     

Sulfate radical-induced incorporation of NO2 group into chlorophenols

Environmental Chemistry Letters - Sulfate radical ( $${\text{SO}}_{4}^{ \cdot - }$$ )-based advanced oxidation processes (SR-AOPs) are promising in situ chemical oxidation technologies that...     

Fitting a parabola to growth data of fishes and some applications to fisheries

Denoting a fish length or weight at age t by X _t , a reference age by t _m , and the corresponding fish length or weight by X _m , the relation between age and length or weight may be described by a parabola as follows: $$\left| {X_t } \right. - X_m \left| = \right.a + b(\left| {t - t_m } \right.\left| ) \right. + c(\left| t \right. - t_m \left| ) \right.^2$$ or $$X_t = A + b(\left| {t - t_m } \right.\left| ) \right. + c(\left| t \right. - t_m \left| ) \right.^2$$ where a, b and c are constants. Each of the above Eqs. describes one curve at ages older than t _m and another one at younger ages, which is made possible by means of the transformation of t to (|t-t _m |). In 2 cases out of 10, the parabola takes the form of a cubic equation. Evidence is given that, as the growth data become fewer, the better fit of the parabola or cubic equation will probably be less in comparison to the von Bertalanffy equation (1938, 1949) as developed by Beverton and Holt (1957) and the power-growth equation (Rafail, 1971), and vice versa. This growth equation is used to derive models for estimating the optimum age and yield for fish populations.     

Hypoxia increases the behavioural activity of schooling herring: a response to physiological stress or respiratory distress?

Atlantic herring, Clupea harengus, increase their swimming speed during low O₂ (hypoxia) and it has been hypothesised that the behavioural response is modulated by the degree of “respiratory distress” (i.e. a rise in anaerobic metabolism and severe physiological stress). To test directly whether a deviation in physiological homeostasis is associated with any change in behavioural activity, we exposed C. harengus in a school to a progressive stepwise decline in water oxygen pressure and measured fish swimming speed and valid indicators of primary and secondary stress (i.e. blood cortisol, lactate, glucose and osmolality). Herring in hypoxia increased their swimming speed by 11–39% but only when was <8.5 kPa and in an unsteady (i.e. declining) state. In parallel with the shift in behaviour, plasma cortisol also exhibited an increase with plasma osmolality was subject to a transient rise at 8.5 kPa and plasma glucose was generally reduced at However, without any rise in anaerobically derived lactate levels, there was no evidence of respiratory distress at any set We show that a shift in physiological homeostasis is indeed linked with an increase in the swimming speed of herring but the physiological response reflects a hypoxia-induced shift in metabolic fuel-use rather than respiratory distress per se. The significance of this behavioural–physiological reaction is discussed in terms of behavioural-energetic trade-offs, schooling dynamics and the hypoxia tolerance of herring.     

The response of Atlantic cod, <Emphasis Type="Italic">Gadus morhua</Emphasis>, to progressive hypoxia: fish swimming speed and physiological stress

Atlantic cod, Gadus morhua, were exposed to a progressive stepwise decline in water oxygen pressure Fish swimming speed and indicators of primary and secondary stress (e.g. blood cortisol and lactate) were measured to assess whether a severe shift in physiological homeostasis (i.e. stress) preceded any change in behaviour or vice versa. Swimming speed increased by 18% when was reduced rapidly from 19.9 kPa to 13.2 kPa and was interpreted as an initial avoidance response. However, swimming speed was reduced by 21% at a moderate level of steady (8.4 kPa) and continued to drop by 41% under progressively deep hypoxia (4.3 kPa). Elevations in plasma cortisol and blood lactate indicated major physiological stress but only at 4.3 kPa, which corresponds to the critical oxygen tension of this species. We propose that the drop in speed during hypoxia aids to offset major stress and is adaptive for the survival of cod in extensive areas of low oxygen.     

Spatiotemporal calibration of atmospheric nitrogen dioxide concentration estimates from an air quality model for Connecticut

Environmental and Ecological Statistics - A spatiotemporal calibration and resolution refinement model was fitted to calibrate nitrogen dioxide ($$\hbox {NO}_2$$) concentration estimates from the...     

Hierarchical log Gaussian Cox process for regeneration in uneven-aged forests

Environmental and Ecological Statistics - We propose a hierarchical log Gaussian Cox process (LGCP) for point patterns, where a set of points $$\varvec{x}$$ affects another set of points...     

Temperature and metabolic rate in sedentary fish from the Antarctic,North Sea and Indo-West Pacific Ocean

Resting metabolic rate was measured in demersal stages of the teleostNotothenia neglecta Nybelin from the South Orkney Islands, Antarctica, from 1985 to 1987. The relationship between and body mass (Mb) conformed to the general relationship , wherea is a proportionality constant andb is the scaling exponent. (mg O₂ h^–1) was found to scale toMb ^{(0.82±0.011)} in the summer (November to April, 1.6 to 1 850 g,n=56) and toMb ^{(0.76±0.013)} in the winter (May to October, 0.9 to 1 850 g,n=57) (values ofb are means ± SD). Although the scaling exponents were significantly different (P<0.01), was similar in the juvenile stages of summer- and winter-caught fish matched for body mass. The effects of activity on oxygen consumption was studied using a Brett respirometer. Adult stages had a factorial aerobic scope for activity of 5.7, which is similar to that reported for demersal fish from temperate latitudes. The effects of temperature on resting metabolism was investigated in fish with similar sedentary lifestyles from the North Sea (Agonus cataphractus andMyoxocephalus scorpius) and the Indo-West Pacific (Paracirrhites forsteri, P. arcatus, Neocirrhites armatus andExallias brevis). Extrapolated values of for the tropical species approached zero at 5 to 10°C. For a standard 50 g fish, for the tropical species at 25°C was in the range 3.4 to 4.4 mg O₂ h^–1, compared with 1.3 mg O₂ h^–1 forNotothenia neglecta at its acclimation temperature. Thus, the maximum metabolic rate of sedentary tropical species at 24°C is likely to be 2 to 4 times higher than inN. neglecta at 0°C. This suggests that the energy available for sustained activity is significantly lower in cold- than in warm-water fish.     

Oxygen consumption inNeomysis americana (Crustacea: Mysidacea), and the effects of naphthalene exposure

Oxygen uptake ( ) of individual mysids was measured in a novel continuous flow respirometer for 24-h periods, and in a sealed chamber respirometer for several hours. Mysids were acclimated 30–100d under conditions which allowed complete life-cycle cultivation. was normalized for mysid size using an unconventional linear regression: log ( ) vs log (body water). Compared to the conventional regression, log ( ) vs log (body mass), the new approach showed two advantages: significantly greater coefficient of determination,r ², and removal of differences in between sexes. Minimum rates of oxygen uptake measured in the continuous flow respirometer were lower than sealed chamber measurements, and may more accurately reflect standard metabolic rate. Hourly data also showed a daily cycle when adjusted to represent a standard size mysid. Exposure to ca 1.1 mg l^-1 naphthalene increased and the range of spontaneous shown by the mysids; exposure to ca 0.1 mgl^-1 naphthalene depressed the range of . Both exposures caused aberrations in the daily cycle.     

A simple and precise method for fitting a von Bertalanffy growth curve

The parameter K of the von Bertalanffy equation, as developed by Beverton and Holt (1957), is first estimated by the relation $$\log _e \left( {dL_t /dt} \right) = A - Kt$$ where dLt/dt denotes growth increments per a unit of age, t denotes age, and A is a constant. The K estimate is used to evaluate L∞; $$L_\infty = \left( {e^K \sum\limits_2^n {L_t - \sum\limits_1^{n - 1} {L_t } } } \right)/\left( {n - 1} \right)\left( {e^K - 1} \right)$$ The L∞ estimate is used to estimate t _o, and to obtain a better estimate for K; $$\log _e \left( {1 - L_t /L_\infty } \right) = - Kt + Kt_0 $$ The K estimate may be used to obtain another estimate for L∞. Solved examples show that a single iteration is sufficient to obtain fitted equations which are, on the average, as precise as equations fitted by the least squares method shown by Tomlinson and Abramson (1961). This new method can be used, with a slight modification, for the second equation given above, if growth data have unequal age intervals. The variance of K, t _o and log _e L∞ can be estimated by applying the simple methods used in the case of straight-line relationships.     

Estimation of abundance of fish populations by capture-recapture experiments

A natural fish population is assumed to be subjected to a number of fishing experiments, during which the captured fish are released after tagging all untagged fish. Assuming that, in thek ^th sampling survey, the tagged and untagged fish are subjected toP _tk andP _uk fishing rates, andS _tk andS _uk survival rates, respectively, the population size can be estimated from an estimate ofP _uk $$\begin{gathered} i.e., 1 - P_{uk} = \hfill \\ P_{tk \cdot } \frac{{S_t (k + 1)}}{{S_u (k + 1)}}\frac{\begin{gathered} Number of fish captured for the first time in \hfill \\ the (k + 1)^{th} survey plus fish belonging to this \hfill \\ group captured later \hfill \\ \end{gathered} }{\begin{gathered} Number of fish captured for the first time in \hfill \\ the k^{th} and captured again in the (k + 1)^{th} \hfill \\ \exp eriment plus fish belonging to this group \hfill \\ which are captured later \hfill \\ \end{gathered} } \hfill \\ \end{gathered}$$ All terms of the right hand side of the above equation are provided by capture-recapture experiments, except the survival rate of untagged fish which may be obtained by other information. This estimate of fishing rate of untagged fish is free from type (A) errors.     

Trophic variation with length in two ommastrephid squids, <Emphasis Type="Italic">Ommastrephes bartramii</Emphasis> and <Emphasis Type="Italic">Sthenoteuthis oualaniensis</Emphasis>

From 1998 to 2001 a total of 200 Ommastrephes bartramii (27 paralarvae) and 170 Sthenoteuthis oualaniensis (14 paralarvae) were sampled from the Central North Pacific. One group of non-paralarval O. bartramii (n = 30) was sampled from farther northwest in 1996. The δ¹⁵N of mantle muscle of non-paralarval O. bartramii ( = 12.4‰) was significantly greater than that of non-parlarval S. oualaniensis ( = 8.1‰) (P < 0.001). The δ¹⁵N of whole paralarvae of O. bartramii ( = 6.4‰) was not significantly different than parlarvalae of S. oualaniensis ( = 6.1‰) (P = 0.528). There was no significant difference between the mantle muscle δ¹⁵N values of male (n = 95, = 13.3‰) and female (n = 18, = 12.9 ‰) O. bartramii greater than 300 mm mantle length (ML) (P = 0.15). There was also no significant difference between the mantle muscle δ¹⁵N values of male (n = 15, = 7.2‰) and female (n = 26, = 7.3 ‰) S. oualaniensis in the same size range (P = 0.41). Overall there was a distinct logistic increase in δ¹⁵N with mantle length for O. bartramii, whereas S. oualaniensis showed an exponential increase in δ¹⁵N with mantle length that was stronger within individual years than with all samples combined. In general, adult O. bartramii are more than a trophic level above S. oualaniensis (4.3‰, 1.3 TLs). Because of the nature of the sampling protocol, this study could not separate spatial and temporal effects on the δ¹⁵N signals from each squid species. This study demonstrates the ability of stable isotope analyses to differentiate trophic levels between squid species as well as track trophic changes across size ranges from paralarvae to adults. Additional research is needed to validate these trophic changes across size within individuals.     

The effect of hypoxia on behavioural and physiological aspects of lesser sandeel, <Emphasis Type="Italic">Ammodytes tobianus</Emphasis> (Linnaeus, 1785)

Lesser sandeel (Ammodytes tobianus) is abundant in near-shore areas where it is a key prey. It exhibits the behaviour of alternating between swimming in schools and lying buried in the sediment. We first determined the species’ standard metabolic rate (SMR), critical partial pressure of oxygen and maximal oxygen uptake The sandeel were then exposed to an acute stepwise decline in water oxygen pressure (18.4, 13.8, 9.8, 7.5, 5.8, 4.0, and 3.1 kPa ). Swimming speed and routine- and post-experimental blood lactate levels were measured, in addition to levels associated with strenuous exercise. The SMR was 69.0 ± 8.4 mg O₂ kg⁻¹ h⁻¹ and the about seven times as high. The was found to be 4.1 kPa. A rapid decrease (within 1 h) in from 18.4 to 3.1 kPa had no significant effect on routine swimming speed (0.9 ± 0.06 bl s⁻¹), but steady levels at the lowest (3.1 kPa) gradually reduced the swimming speed by 95% after 40 min. The routine blood lactate levels were 2.2 ± 0.6 mmol l⁻¹, while the levels in the strenuously exercised groups were significantly higher with 5.4 ± 1.6 and 5.8 ± 1.3 mmol l⁻¹. The highest levels were observed in post-experimental fish with 7.5 ± 2.7 mmol l⁻¹. We argue that, as sandeel showed no decrease in swimming speed (to offset stress) nor an increased speed to escape the hypoxia, the fish either rely on a low SMR and being a reasonable strong oxygen regulator as a mean to cope when exposed to acute hypoxia, or that the hypoxia simply developed too fast for the fish to decide on an appropriate strategy. Not showing a behavioural response may in the present case be maladaptive, as the consequence was major physiological stress which the fish however appears tolerant towards. The high routine blood lactate levels suggest that anaerobic metabolism is associated with swimming in sandeel, which may be related to the specific lifestyle of the fish where they regularly bury in the sediment.     

Oxygen consumption and ammonia excretion of<Emphasis Type="Italic"> Octopus vulgaris</Emphasis> (Cephalopoda) in relation to body mass and temperature

The common octopus, Octopus vulgaris Cuvier, is of great scientific and commercial importance and its culture is becoming an area of increasing interest. In this study, the combined effects of temperature (T) and body mass (M) on the routine oxygen consumption rate (R) and ammonia excretion rate (U) in O. vulgaris were quantified. The experiments were conducted in a closed seawater system, and great care was taken to reduce handling stress of the animals. Temperature, salinity, pH and ammonia, nitrite, nitrate and phosphate concentrations were monitored and controlled during the experiment. The following predictive equations were evaluated: at temperatures between 13°C and 28°C and at temperatures between 15.5°C and 26°C (T_a is degrees Kelvin and M in gram). O/N ratios showed that O. vulgaris has a protein-dominated metabolism. No significant relationship between the O/N ratio and body mass or temperature was found. Sex had no significant effect on the oxygen consumption rate or on the ammonia excretion rate. For other octopod species, the dependence of metabolic rate on temperature does not differ with that for O. vulgaris.Communicated by O. Kinne, Oldendorf/Luhe     

Oxygen consumption of the semi-terrestrial crab <Emphasis Type="Italic">Pachygrapsus marmoratus</Emphasis> in relation to body mass and temperature: an information theory approach

Pachygrapsus marmoratus is a semi-terrestrial crab and the most common grapsid crab in the intertidal belt of rocky shores throughout the Mediterranean Sea, Black Sea and northeastern Atlantic. In this study, the combined effects of temperature (T), body mass (M), and sex (S) on the routine oxygen consumption rate (R) in P. marmoratus were quantified. The blotted wet body mass of the specimens ranged between 43 mg and 18.0 g, and five test temperatures were used between 13.5 and 28.0°C. Six candidate models that reflected different assumptions regarding the dependence of R on S and T were compared. Model selection was based on Kullback–Leibler’s information theory and Akaike’s information criterion (AIC). The model had the highest support by the data (E is the activation energy, B = 8.618 × 10⁻⁵ eV K⁻¹ is Boltzmann’s constant, T _a is the absolute temperature in Kelvin, and b the allometric scaling exponent); for P. marmoratus it was found that No sex dependence of R was supported by the data. Following a multi-model inference (MMI) approach, the mean (± SE) allometric exponent was 0.750 (± 0.013) having a 95% (bootstrap) confidence interval of 0.726–0.774. Thus, it was established that P. marmoratus follows Kleiber’s 3/4 law, as seems to be generally true for intertidal crabs. The allometric exponent was independent of temperature as has also been reported for many other marine invertebrates (at normal temperatures). Q ₁₀ values were relatively low, indicating wide thermal tolerance of the species. Model selection based on information theory is recommended for respiration studies, as an effective method in finding a parsimonious approximating model. MMI by model averaging, based on Akaike weights, is an effective way to make robust parameter estimations and deal with model selection uncertainty.     

Oxygen and carbon dioxide exchange in the polychaete Nereis virens: influence of ventilation activity and starvation

The influence of ventilation activity and starvation on O₂ uptake and CO₂ production in the polychaete Nereis virens Sars was investigated during September 1986 using worms collected on intertidal flats outside the Nærå Strand estuary, Denmark. The activity level, measured as ventilation rate, , was linearly related to active O₂ uptake, , for worms inhabiting artificial burrows (i.e. tubes) in the laboratory. at 16°C was two and four times the extrapolated standard O₂ uptake ( =0) when was 100 and 500 ml g^-1 h^-1, respectively. The use of tubes had no significant effect on N. viren's temporal ventilation pattern, D_v, compared to natural burrows in sediment. The ventilation rate, , however, was 2 to 3 times higher in tubes than in burrows. Starvation affected both ventilation and gas exchange. increased slightly during the first six days remaining constant thereafter. D_v, on the othe hand, decreased during the first six days followed by a gradual increase to Day 20. The observed decrease in D_v (%) from Day 0 to 1 was attributed to insufficient acclimation of the worms. The time integrated ventilation rate, × D_v, increased gradually throughout the 20 d starvation period. and declined rapidly during the first days of starvation. After 10 d the gas exchange reached steady levels at about 50% of the initial rate. The observed decrease in metabolic rate during starvation was explained by a rapid initial reduction in specific dynamic action (SDA) followed by a gradual exhaustion of readily available metabolic reserves, e.g. glycogen and lipids.     

Comments on “turbulent velocity profile in fully-developed open channel flows”

In a recent paper published in this journal, Bonakdari et al. (Environ Fluid Mech 8:1–17, 2008) presented a new formulation of the vertical velocity profile in the central portion of steady fully developed turbulent open-channel flows which is based on an analysis of the Navier–Stokes equations. The predicted mean streamwise velocity profiles presented by the authors represent dip phenomenon (maximum velocity below the free surface). The discusser would like to point out some contradictions and an error in the main demonstration. This error appears in the right-hand side term of the main Eq. 22 (Environ Fluid Mech 8:1–17, 2008) in the parameter α. Our corrected demonstration shows that α is equal to and not to as obtained by the authors (Environ Fluid Mech 8:1–17, 2008). The values of α used by the authors are under-estimated by 1, this difference has a significant effect on velocities and therefore will involve a difference between measured and predicted velocity profiles. Finally, the assumption of at the free surface is in contradiction with predicted velocity profiles.     

In vitro antioxidant and antibacterial activities of certain 3-{4-(5-mercapto-1,3,4-oxadiazole-2-yl)phenylimino}-indolin-2-one derivatives

A new series of 5- or 7-substituted 3-{4-(5-mercapto-1,3,4-oxadiazol-2-yl)phenylimino}-indolin-2-one derivatives were screened for in vitro antioxidant and antimicrobial activities. The results of this study revealed that all synthesized compounds were significantly scavenged DPPH free radicals in a concentration-dependant manner. The IC₅₀ values of all test compounds were found to be between 18.34 and 50.54?µM. All compounds significantly inhibited growth of bacteria and most of the minimum inhibitory concentration values were between 20 and 100?mg?mL^?1 indicating potent to moderate antibacterial activity. In conclusion, 3-{4-(5-mercapto-1,3,4-oxadiazole-2-yl)phenylimino)-5 or 7-substituted indolin-2-ones derivatives exhibited moderate antioxidant and antimicrobial activities.