Daily Growth Rate Research Articles

Deep learning modeling of public’s sentiments towards temporal evolution of COVID-19 transmission

Public sentiments towards global pandemics are important for public health assessment and disease control. This study develops a modularized deep learning framework to quantify public sentiments towards COVID-19, followed by leveraging the predicted sentiments to model and forecast the daily growth rate of confirmed COVID-19 cases globally, via a proposed G parameter. In the proposed framework, public sentiments are first modeled via a valence dimensional indicator, instead of discrete schemas, and are classified into 4 primary emotional categories: (a) neutral; (b) negative; (c) positive; (d) ambivalent, by using multiple word embedding models and classifiers for text sentiments analyses and classification. The trained model is subsequently applied to analyze large volumes (millions in quantity) of daily Tweets pertaining to COVID-19, ranging from 22 Jan 2020 to 10 May 2020. The results demonstrate that the global community gradually evokes both positive and negative sentiments towards COVID-19 over time compared to the dominant neural emotion at its inception. The predicted time-series sentiments are then leveraged to train a deep neural network (DNN) to model and forecast the G parameter by achieving the lowest possible mean absolute percentage error (MAPE) score of around 17.0% during the model’s testing step with the optimal model configuration.

Heavy Metal Depuration Steps for Gracilaria chilensis in Outdoor Culture Systems.

Seaweed aquaculture is affected by natural and anthropogenic stressors, which put the biomass productivity of the cultures at risk. Seaweed biomass for commercial purposes, principally in pharmaceutical and/or nutraceutical applications, needs to be free of pollutants; therefore, controlled cultures have relevance in regulating the quality of biomass. The aim of this work was to demonstrate the successful utilization of controlled outdoor cultures to remove excess heavy metal accumulation in Gracilaria chilensis, an important commercial seaweed farming model. Specifically, we designed a simple and operational heavy metal depuration protocol, utilizing seawater and tap water removal, which permitted the concentration reduction of 10 heavy metals, including As, Cu, and Cd but not Zn, from the biomass at 7 days of culture. The percentage of depuration of the heavy metals ranged from 32 to 92% at 7 days, which was maintained throughout 21 days of culture. During the culture period, the monitored physicochemical parameters (temperature, salinity, and dissolved oxygen, among others) remained stable, with an increase in the daily growth rate (DGR% d−1) of the biomass recorded after 14 days of culture. Consequently, the experimental setup was successful for heavy metal depuration, which highlights the importance of controlled outdoor cultures as important tools of sustainability.

Effects of microalgal diet on growth, survival and fatty acid composition of larvae rock oyster Striostrea prismatica (Gray, 1825)

The biochemical nature and composition of fatty acids (FA's) in microalgae influence the nutritional quality and efficiency of this food source in bivalve larviculture. This research analyses the effect FA's content of Chaetoceros gracilis and Tisochrysis lutea on the FA's composition, growth and survival of Striostrea prismatica larvae. We analysed the FA's profiles of the microalgae, and the tissue of the larvae during a S. prismatica larviculture at day 1 (“D” larvae), day 8 (umbonate larvae) and day 22 (pediveliger) post fertilization (PF). Larvae growth and survival were evaluated during two phases: phase I from day 1 to day 8 PF and phase II from day 9 to day 22 PF. In phase I, we recorded a daily growth rate of 4.76 μm.day−1, while in phase II we recorded increases of 13.24 μm.day−1. In phase I, survival was 36.6%, and decreased further to 9.3% at the end of phase II. The sharp decrease in survival and low growth during phase I could possibly be explained by a specific nutritional deficiency of the microalgae diet (absence of FA's 15:0, 20:4n-3, 20:4n-6 and 22:5n- 3), especially if we consider the starting FA's profile of the “D” larvae. The larvae showed a high nutritional requirement for palmitic, stearic and oleic FA's and long-chain PUFA's, especially 20:5n-3 and 22:6n-3. The absence of these FA's in the diet and their presence in the larval profile suggest that S. prismatica could have the ability to synthesize these FA's; however, more research is needed to corroborate this hypothesis.

Improving quality of cassava peel meal as raw material for tilapia feed

Cassava peel meal (CPM) has potential as a raw material for fish feed due to its abundant availability and good nutritional content. The high crude fiber content inhibits the use of CPM as a raw material for fish feed. Therefore, this study aims to evaluate the effect of Aspergillus niger fermentation of CPM on dietary nutrient digestibility and growth performance of tilapia (Oreochromis niloticus). It was conducted in 2 stages. The first stage was a fermentation process of CPM, which used a factorial randomized design consisting of a dose difference of A. niger, namely 10, 15, 20, 30 g.kg-1 and a fermentation time of 0, 12, 24 hours with 3 replications each. At a dose of 1.5% of A. niger during 24 hours of fermentation, the crude fiber content of fermented CPM was reduced up to 7.19%. the second stage was a 45 days feeding trial on tilapia used a completely randomized design consisting of 3 different treatments with 3 replications, namely: reference feed, unfermented cassava peal meal based diet (CPMD), and A. niger fermented CPMD. A. niger fermented CPMD showed an increase in growth, dry matter, protein, energy, and raw material digestibility, as well as daily growth rate compared to unfermented CPMD. The daily growth rate of fermented CPMD of 1.32%/day was significantly higher with P0.05 than the unfermented CPMD of 0.72%/day. Furthermore, the digestibility value of material test in the fermented CPMD (48.73%) was significantly higher (P0.05) than unfermented CPMD (11.74%). These results indicate that A. niger fermented CPM has the potential to be used as raw material for tilapia fish feed. Keywords:Aspergillus nigerFermentationTilapiaCrude fiber

Intra-annual radial growth of Abies georgei and Larix potaninii and its responses to environmental factors in the Baima Snow Mountain, Northwest Yunnan, China.

Using high-resolution dendrometers, we monitored the intra-annual stem radial variations of Abies georgei and Larix potaninii in the subalpine coniferous forest in Baima Snow Mountain, Northwest Yunnan Province. The seasonal dynamics of stem radial growth of both species and their responses to environmental factors were analyzed. The results showed that the stem radial growth of A. georgei and L. potaninii mainly occurred during April to August, with the maximum growth rate in June. Compared with A. georgei, L. potaninii showed an earlier start but later cessation of stem radial growth, resulting in longer growth duration. Annual radial growth and maximum radial growth rates of L. potaninii were slightly higher than those of A. georgei. Daily growth rate of A. georgei was positively correlated with precipitation, but negatively correlated with vapor pressure deficit and air temperature. Daily growth rate of L. potaninii was positively correlated with precipitation, but negatively correlated with soil volume water content and vapor pressure deficit. Radial growth of A. georgei and L. potaninii was limited by water availability, with L. potaninii being more sensitive to moisture. Under the background of global warming, the increase of plant transpiration and soil evaporation might further aggravate soil water loss and reduce water availability for plants, which would make A. georgei and L. potaninii more vulnerable to drought stress.

PENGARUH DOSIS PAKAN BUATAN TERHADAP KELULUSHIDUPAN DAN PERTUMBUHAN LARVA IKAN NILEM (Osteochilus vittatus)

Nilem fish is a native Indonesian commodity that has been cultivated for a long time by the community. Nilem fish has the potential to be developed into superior aquaculture products. Nilem fish cultivation is profitable in terms of economy, environmental sustainability, and aquaculture production. This study aims to determine the effect of giving different feed doses on survival and growth of nilem fish (Osteochilus vittatus) larvae. The research design used in this study was a completely randomized design (CRD) consisting of 5 treatments and 5 replications. Data analysis was carried out with normality test and homogeneity test then continued with ANOVA (Analysis of Variance) test and to find out the difference between one treatment and another, a further test was carried out, namely the Least Significant Difference Test (BNT). The results of this study showed that the best percentage of survival, absolute weight growth and daily growth rate of nilem fish (Osteochilus vittatus) larvae was obtained in treatment B (4% of feed dose from biomass) with successive values ​​of 97.72% ± 2.65, 0.22 grams ±2.65 and 8.23% ±6.76. This is because the amount of feed given can be utilized optimally by fish larvae so that it is not only for survival but also can support the growth process, and there is no turbidity (dissolved or suspended organic matter) in the live fish media which can result in inhibition of the growth of fish larvae.

The impact of mask-wearing in mitigating the spread of COVID-19 during the early phases of the pandemic.

Masks have been widely recommended as a precaution against COVID-19 transmission. Several studies have shown the efficacy of masks at reducing droplet dispersion in lab settings. However, during the early phases of the pandemic, the usage of masks varied widely across countries. Using individual response data from the Imperial College London-YouGov personal measures survey, this study investigates the effect of mask use within a country on the spread of COVID-19. The survey shows that mask-wearing exhibits substantial variations across countries and over time during the pandemic's early phase. We use a reduced form econometric model to relate population-wide variation in mask-wearing to the growth rate of confirmed COVID-19 cases. The results indicate that mask-wearing plays an important role in mitigating the spread of COVID-19. Widespread mask-wearing associates with an expected 7% (95% CI: 3.94%-9.99%) decline in the growth rate of daily active cases of COVID-19 in the country. This daily decline equates to an expected 88.5% drop in daily active cases over 30 days compared to zero percent mask-wearing, all else held equal. The decline in daily growth rate due to the combined effect of mask-wearing, reduced outdoor mobility, and non-pharmaceutical interventions averages 28.1% (95% CI: 24.2%-32%).

The median age of a city’s residents and population density influence COVID 19 mortality growth rates: policy implications

BackgroundSARS-CoV-2 is an infectious virus, which has generated a global pandemic. Israel was one of the first countries to vaccinate its population, inaugurating the program on December 20, 2020. The objective of the current study is to investigate the projected daily COVID19 mortality growth rate with higher median age and population size of cities under two scenarios: with and without the BNT162b2 Pfizer vaccination against the SAR-COV2 virus.MethodsThis study employs a panel data-set. We follow the COVID19 mortality growth rate in each of the 173 Israeli cities and towns starting from March 21, 2020 (10 days after the first documentation of COVID19 cases in Israel) until September 21, 2021, where the BNT162b2 Pfizer vaccinations were available starting from December 20, 2020.ResultsReferring to the median age of municipal residents, findings suggest that the BNT162b2 Pfizer vaccinations attenuate the rise in anticipated daily mortality growth rate for cities and towns in which the median population age is 30 years old (the range in median age among the residents in the municipalities surveyed is 11–41 years). Moreover, referring to population size of cities, findings demonstrate that while under the scenario without vaccination, the daily mortality growth rate is anticipated to rise, under a comparable scenario with vaccination, daily mortality growth rate is anticipated to drop.ConclusionsIn crowded cities, where the median age is high, two perspectives of early and intensive public policy interventions are clearly required. The first perspective is extensive medical treatment, namely, extension of availability of medical physical and online services; dispensing designated medications; expansion of hospitalization facilities and information services particularly to susceptible populations. All measures will be taken with attention to age accessibility of these means. The second perspective is prevention via establishment of testing and vaccination complexes; elevation of dedicated health services, generating selective lockdowns; education for increasing awareness to social distancing, wearing masks and other preventive means.

A delayed modulation of solar ultraviolet radiation on the COVID‐19 transmission reflects an incubation period

Laboratory experiments have revealed the meteorological sensitivity of the coronavirus disease 2019 (COVID‐19) virus. However, no consensus has been reached about how outdoor meteorological conditions modulate the virus transmission as it is also constrained by non‐meteorological conditions. Here, we identify the outbreak's evolution stage, constrained least by non‐meteorological conditions, by searching the maximum correlation coefficient between the ultraviolet flux and the growth rate of cumulative confirmed cases at the country level. At this least‐constrained stage, the cumulative cases count around 1300–3200, and the count's daily growth rate correlates with the ultraviolet flux and temperature significantly (correlation coefficients r = −0.54 ± 0.09 and −0.39 ± 0.10 at p<0.01, respectively), but not with precipitation, humidity, and wind. The ultraviolet correlation exhibits a delay of about 7 days, providing a meteorological measure of the incubation period. Our work reveals a seasonality of COVID‐19 and a high risk of a pandemic resurgence in winter, implying a need for seasonal adaption in public policies.

Qualitative Analysis of Bifurcation: The First Border Steady-State Solution

This paper examines the bifurcation analysis of two interacting ecological species in a qualitative manner. In the modelling of competition interaction between two ecological species, when the daily intrinsic growth rate is varied while other model parameters are fixed, the fundamental qualitative changes of the borders steady-state solution are studied. This steady-state solution is stable if and provided is a positive parameter and is one of the model parameters. It passes through a bifurcation point and and is unstable if and .

Physical profile and chemical composition of a novel fabricated Kaolina as alternative growing media in aquaponics

The physical profile and chemical composition of growing media are vital in evaluating fish waste filtration efficiency and plant growth performance in aquaponics. The present study reported and compared the physical and chemical evaluation of the novel fabricated Kaolina, gravel, and commercially used lightweight expanded clay aggregate (LECA) as growing medias in aquaponics. Field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy (FESEM-EDX) was utilized to analyze the growing media's chemical composition and structural characterization. The resultant effect of these growing medias on water quality and the growth performance of Clarias gariepinus and Lactuca sativa were also reported. Kaolina exhibited an excellent physical profile (42.95 ± 1.39%) in water absorption capacity as compared to LECA (35.90 ± 1.28%) and gravel (1.97 ± 0.25%), showing a significant difference at p < 0.05. The addition of 25% w/w Musa paradisiaca peel in the fabrication of Kaolina gives an added value of 88.0% of K and 100% of P elements, which show a significant difference (p < 0.05) compared to LECA. The results obtained reveal a better daily growth rate (DGR) and relative growth rate (RGR) of L. sativa at 0.57 ± 0.02 cm day−1 and 0.21 ± 0.00 g day−1, respectively. Results indicated that the porous structure of growing media could contribute to the high-water retention capability and slow the water desorption process. Hence, it could increase the ability of the growing media to hold nutrients for plant intake, resulting in higher removal percentage of nutrients in aquaponics system. Kaolina gives the highest nutrient removal percentage of TAN (96.86 ± 1.50%), NO2− (83.56 ± 1.27%), NO3−(77.55 ± 0.48%), and PO43− (79.46 ± 0.42%). The results also shown growing media has considerable impacts on nutrient removal, which contribute to the aquaponic productions.

Exploring the contagion effect of social media on mass shootings

Social media plays a prominent role in the spread of mass shootings. Moreover, it brought about a significant contagious effect on future similar incidents. Therefore, we explore Machine Learning (ML) models to forecast the change in the public’s attitudes about mass shootings on social media over time. These ML models include Support Vector Machine (SVM), Logistic Regression (LR), and the optimized Deep Neural Networks based on an Improved Particle Swarm Optimization algorithm (IPSO-DNN). We then propose a self-excited contagion model to predict the number of mass shootings by focusing on the spread of public attitudes on Twitter. We also improve the proposed contagion model with the consideration of social distancing and the daily growth rate of COVID-19 cases, as to predict and analyze mass shootings under the COVID-19 pandemic. Experimental results demonstrate that the proposed contagion models perform very well in predicting future mass shootings in the United States.

Age, Growth and Population Structure Analyses of the Purpleback Flying Squid Sthenoteuthis oualaniensis in the Northwest Indian Ocean by Beak Microstructure

To explore the feasibility of using beak microstructure information to estimate the age of Sthenoteuthis oualaniensis, the microstructures of the upper beaks of individual squid were applied in this work to analyze the ages and growth patterns of squid caught from February–May 2019 and from October–December 2020 in the northwest Indian Ocean. The results indicated that the squid samples in the two years were no older than 9 months, and the samples in 2019 were autumn population and 2020 were spring population. The linear growth model of the autumn population (2019) was the best model for describing the relationship between age and ML, while the power model of the spring population (2020) was the best for describing the relationship between age and ML. The maximum instantaneous growth rate (IGR) and absolute daily growth rate (AGR) values of the spring population were 0.24%/d and 1.09 mm/d, respectively, occurring in squid between 200 and 220 days of age. The maximum IGR and AGR values of the autumn population were 0.69%/d and 1.73 mm/d, respectively, occurring in squid between 200 and 240 days of age. The period from 141–260 days (5–8 months) was considered to correspond to the subadult stage in the whole life history of S. oualaniensis in the Northwest Indian Ocean. The beak microstructure information can be effectively applied to estimate the age of S. oualaniensis individuals.

Pengaruh Bobot Bibit Awal yang Berbeda terhadap Laju Pertumbuhan Rumput Laut Kappaphycus alvarezii dengan Metode Lepas Dasar

There are several factors that will inhibit the growth of seaweed when the cultivation process is the initial stocking density in the off-bottom method. This study aims to determine the effect of different awa seed weights on the growth rate of K. alvarezii seaweed which will provide information regarding the optimal initial weight. This research was carried out in April-May 2021 for 42 days with an acclimatization period of 3 days and preparation of containers for 7 days. Berakit Village, Teluk Sebong District, Bintan Regency, Riau Islands Province. The method used is an experimental method with a completely randomized design (CRD) with 3 treatments with 3 replications. Where the weight of the seeds of treatment A: 50 g, B 100 g, C 150 g, The results of the analysis of the highest absolute growth were obtained in seaweed with initial seed weight of 50 treatments. g with the highest average value of 207.75±9.02b, followed by treatment of 150 g with an average value of 166.78±6.96a and the lowest treatment of 100 g with an average value of 157.04±1.48a. Meanwhile, the highest daily specific growth rate was focused on the 50 g treatment with an average value of 4.95±0.22% b followed by the 150 g treatment with an average value of 3.97±0.17% and the lowest treatment was in the 100 g treatment with an average value of 3.74± 0.04%. Treatment of different initial seedling weight with off-base method gave a significant effect on Absolute Growth (PM) and Daily Specific Growth Rate (LPS) during maintenance.

Improvement of breeding methods of predatory mites Neoseiulus cucumeris and Transeius montdorensis for biological plant protection

The possibility of breeding of phytoseiid predatory mites Neoseiulus cucumeris and Transeius montdorensis using hardwood sawdust as a substrate and frozen dried fruit mite (Carpoglyphus lactis) as feed was studied. The number of larvae produced by N. cucumeris was 31.5 % lower on frozen feed in sawdust than in the control, while in T. montdorensis it was lower by 47.7 %. The number of individuals surviving to adulthood compared to the control was lower by 28.6 % and 42.9 %, respectively. The maximum daily growth rate of the population was reduced relatively to the control by 3.7 individuals in N. cucumeris, and by 4.5 in T. montdorensis –. On frozen feed in bran, N. cucumeris produced 20.5 % fewer larvae than in the control, T. montdorensis – 35.1 % fewer larvae. The number of individuals surviving to adulthood was reduced by 18.3 % and 35.3 %, respectively, compared to the control. The maximum daily population growth rate was 1.7 individuals lower than in the control in N. cucumeris, and – 3.9 individuals lower in T. montdorensis. On live feed in sawdust, larval production was similar to the control (lower by 1.1 % in N. cucumeris and 14.2 % in T. montdorensis). The number of individuals was reduced relatively to the control by 1.7 % and 14.8 %, respectively. The maximum daily population growth rate in N. cucumeris is slightly lower (by 0.7 individuals) than in the control, and in T. montdorensis it even exceeded the control by 0.6 individuals per day. Our results showed the possibility of using sawdust as a cheaper substrate for breeding of both species of predatory mites and poor performance of the frozen feed compared to the live one.

Growth and survival rates of dispersing free embryos and settled larvae of pallid sturgeon (Scaphirhynchus albus) in the Missouri River, Montana and North Dakota

We released nearly 1.0 million 1-day post-hatch (dph) and 5-dph pallid sturgeon (Scaphirhynchus albus) free embryos in the Missouri River on 1 July 2019 and sequentially captured survivors at multiple sites through a 240-km river reach to quantify daily growth and survival rates during the early life stages. Genetic analysis was used to assign captured fish to released family lots and known ages. Growth rate was similar (0.74–0.75 mm day−1) between the 1- and 5-dph age groups during the 3–4-day dispersal period when water temperature averaged 16.8 °C. Daily survival rate was 0.64 during 1–4 dph for the original 1-dph age group and 0.80 during 5–7 dph for the original 5-dph age group. Total survival during free embryo dispersal (hatch to 9 dph) was estimated as 0.0437. The transition from dispersing as free embryos to settling as benthic larvae was verified for fish originally released as 5 dph. Growth of settled larvae was quantified with a Gompertz model through 75 dph (9 September; 112 mm) when water temperature was 18.8–21.0 °C in the rearing areas. Settled larvae had an estimated daily survival rate of 0.96, and estimated total survival during 9–75 dph was 0.0714. This study provides the first empirical survival estimates for pallid sturgeon early life stages in natural settings and is one of few studies reporting similar information for other sturgeon species. Applications of this work extend to pallid sturgeon restoration programs where population models are being developed to predict recruitment potential and population responses to river management alternatives.

Application of pumpkin flour to the diet of Barramundi Lates calcarifer fingerling

Barramundi Lates calcarifer is a high economic value fish in Indonesia and Southeast Asia countries. However, the aquaculture system still experiences problems, including the high cost of production, specifically from feed, which is due to its relatively slow growth and low digestibility. Therefore, this study aims to determine alternative ingredients that can be used in the fish diet to improve feed utilization and growth performance using pumpkin flour Cucurbita moschata. A completely randomized design (CRD) with 6 treatments and 3 replications was adopted in this study. The tested diet was (A) diet without pumpkin flour (control), (B) with 5% (C) 10% (D) 15% (E) 20%, and (F) 25%. The size of the Barramundi samples was 3-4 cm on average and the body weight was 1-3 g at the stocking density of 15 fish/container. The fish fed as much as 10% body weight daily, which is divided into 2 times, namely 08.00 AM and 4.00 PM for 60 days. The results showed that the addition of pumpkin flour had a significant effect on weight gain, daily and specific growth rate, survival, feed efficiency, conversion ratio, and carcass protein (P0.05). The diet with 5% pumpkin flour gave the best results over other treatments, with an average weight gain of 0.761 g, feed conversion of 1.578, feed efficiency of 63.455%, and a daily and specific growth rate of 0.012 g and 0.738%, respectively, The highest carcass protein content was found in the control treatment with a value of 18.210%, which was not significantly different from the 5% pumpkin flour treatment. Therefore, it is concluded that pumpkin flour can be added to the Barramundi diet as much as 5%. Keywords: Barramundi, Snapper, pumpkin, feed utilization

Beak Microstructure Estimates of the Age, Growth, and Population Structure of Purpleback Flying Squid (Sthenoteuthis oualaniensis) in the Xisha Islands Waters of the South China Sea

This study aimed to explore the feasibility of using an upper beak microstructure to estimate the age of purpleback flying squid (Sthenoteuthis oualaniensis). From these microstructures, the age and growth of squid caught from January to March and May to August in 2018, 2019, and 2020 in the waters surrounding the Xisha Islands in the South China Sea were determined. We found three typical growth zones (the hood region, crest region, and axis), abnormal increments (checks), and erosion in the beak examination. The average dorsal mantle length (ML) of males and females was 112.13 (±15.23 mm) and 119.67 mm (±24.50 mm), respectively, and no squid were older than 10 months. The peak hatching dates, according to back calculations, were from October to January of the next year. All sampled squid belonged to the autumn/winter cohort. Significant sex differences were found in the relationship between ML and age in squid with similar growth patterns. Exponential models best described the relationships of ML with age and body weight (BW) for both sexes. However, a linear model best described the relationship between age and upper rostrum length (URL). The maximum absolute daily growth rates (AGR) of BW were reached during days 240–270 for both sexes. The maximum AGRs in ML were reached during days 180–210 and 240–270 for males and females, respectively. The period of 120–150 days (4–5 months) was considered the sub-adult stage of S. oualaniensis in the Xisha Islands waters of the South China Sea. This study confirmed that the beak microstructure provides good age estimates for purpleback flying squid (S. oualaniensis).

Wastewater Treatment Efficiency by a Freshwater Phylactolaemate Bryozoan and Experimental Feeding with Protozoa

The wastewater treatment ponds of the King’s Royally Initiated Laem Phak Bia Environmental Research and Development (LERD) Project in west-central Thailand provide habitats for freshwater bryozoans, which are colonial invertebrate animals. Bryozoans sieve food particles out of the water using a retractable lophophore and can play an important ecological role in wastewater treatment. In this unique environment, we: (1) investigated the efficiency of a phylactolaemate bryozoan (Plumatella casmiana) in wastewater treatment, measured by BOD5, chlorophyll a and turbidity; and (2) determined the role of protozoans in the diet of the bryozoan P. casmiana. Comparison of growth rate and fecal pellet characteristics between protozoan-fed bryozoans and phytoplankton-fed bryozoans was investigated. At the end of our wastewater treatment experiment, water quality parameters were markedly improved in the treatment with bryozoans compared to the control (without bryozoans). The treatment efficiency levels for BOD5, turbidity, and chlorophyll a were 24.04%, 59.21%, and 55.13%, respectively. The growth rates of bryozoans in the experimental treatment increased over time. Our study also revealed that this bryozoan can feed on a diet of protozoans under experimental conditions. However, the average daily growth rate of protozoan-fed bryozoans -20 zooids per day was lower than that of phytoplankton-fed bryozoans 19 zooids per day. This may have been due to incomplete digestion of protozoans or insufficient nutrition in the bryozoans. The results from this study provide better understanding of bryozoan ecology and their role in wastewater treatment systems.

Performance of Holstein calves receiving equal solids per day from high-solids milk and milk replacer blend once or twice daily combined with dry versus wet fine-particle starter diet

This study examined the effects of frequency of feeding high-solids milk and milk replacer (MMR) blend combined with dry matter (DM) content of starter feed on the performance of dairy calves. Forty-eight Holstein calves (40.2 ± 3.33 kg of body weight) were randomly assigned to 1 of 4 treatments in a completely randomized design. Based on a combination of 2 MMR feeding frequencies (once versus twice daily) and 2 starter DM levels (91.1 and 50% DM), 4 treatments were designed as (1) once daily + dry starter feed (OD), (2) once daily + wet starter feed (OW), (3) twice daily + dry starter feed (TD), and (4) twice daily + wet starter feed (TW). The amount of milk replacer powder added to whole milk was adjusted at each feeding frequency to ensure that calves received similar solids from the MMR blend via the twice-daily (total solids = 18.6%) or once-daily (total solids = 31.0%) programs. Starter intake in the preweaning period did not differ between treatments (average 0.39 kg of DM/d), but the postweaning starter intake was greater in calves fed the wet starter (OW and TW) than in those fed the dry starter (OD and TD). Calves receiving the high-solids MMR blend twice versus once daily grew faster before weaning, which was reflected by a greater weaning weight in the TD and TW groups (88.9 kg) than in the OD and OW groups (83.2 kg). The daily growth rate after weaning did not differ between treatments and averaged 1.15 kg/d. Gain-to-feed ratio during the preweaning period was greater in calves from TD and TW (mean 0.67) than in calves from the OD or OW groups (mean 0.58). Postweaning gain-to-feed ratio was not different among treatments and averaged 0.38. Days to first diarrhea and duration of diarrhea (4.66 ± 0.38), as well as days that animals were treated with antibiotics, remained unaffected with treatments. Although preweaning body weight gain was lower with once-daily milk feeding, calves were twice as heavy at weaning as at birth in both milk feeding programs regardless of starter moisture content, which may qualify the once-daily milk feeding program as a cost-effective management strategy in commercial calf-rearing operations. Feeding solutions with a high solids content (above 15%) may be associated with an increased risk of abomasal bloat and should be used with caution.