716 research outputs found
Modelling and Analysis of the Simple Water Heater System
Modelling is nothing but converting physical information in to mathematical form. Mathematical model plays vital role for identification and analysis of the system. In this paper simple water heater system was taken as test bench. Considering system parameters mathematical model of first order with time delayed was derived. Model was simulated in the simulation tool MATLAB and systems response has been studied by changing various parameters like static gain, time constant, delay time and noise, for applied step input.Response of the simulated system was analysed and compare with the actual real time system parameters. Keywords: Modelling, Analysis, MATLAB, Water heater system.DOI:http://dx.doi.org/10.11591/ijece.v1i1.5
Logistic regression analysis of employment behavior data using randomized response technique
Direct survey techniques deal with collecting information on sensitive issues data, such as induced abortion, drug addiction, and so on. RR (randomized response) techniques are available for many interviewees, who do not feel comfortable to disclose their personal data due to privacy risks. RR techniques are used in the estimation of the number of people having a sensitive attribute say A. When the research is conducted on the disgraceful or ignominious characteristics of persons like rash driving, tax elusion, induced abortion, testing HIV (human immunodeficiency virus) positive etc., RR techniques are used to make sure that the estimates obtained are efficient and unbiased. During these types of surveys, privacy of the respondent is also managed. Among others, the conflict between efficiency and protection of privacy was also discussed by Nayak in 1994. In RR-related techniques, the SRS (simple random sampling) is statistically used in the sample selection. In this paper, RR procedure is used that allows us to estimate the population proportion in addition to the probability of providing a truthful answer. This study also quantifies a method for the estimation of the model having one variable (univariate) while studying logistic regression, where the dependent variables are subject to RR. In addition, an efficiency comparison is carried out to investigate the performance of the proposed technique. It is also assumed that during the study, the respondents will respond keeping in view the instructions of the RR design. The general idea about findings of current study, though, is so as to perform RR techniques comparatively fine
Prevalence of subclinical ketosis and relationships with postpartum diseases in European dairy cows
Subclinical ketosis (SCK) is defined as concentrations of β-hydroxybutyrate
(BHBA) ≥ 1.2 to 1.4 mmol/L and it is considered a gateway condition for other
metabolic and infectious disorders such as metritis, mastitis, clinical
ketosis, and displaced abomasum. Reported prevalence rates range from 6.9 to
43% in the first 2 mo of lactation. However, there is a dearth of information
on prevalence rates considering the diversity of European dairy farms. The
objectives of this study were to (1) determine prevalence of SCK, (2) identify
thresholds of BHBA, and (3) study their relationships with postpartum
metritis, clinical ketosis, displaced abomasum, lameness, and mastitis in
European dairy farms. From May to October 2011, a convenience sample of 528
dairy herds from Croatia, Germany, Hungary, Italy, Poland, Portugal, Serbia,
Slovenia, Spain, and Turkey was studied. β-Hydroxybutyrate levels were
measured in 5,884 cows with a handheld meter within 2 to 15 d in milk (DIM).
On average, 11 cows were enrolled per farm and relevant information (e.g.,
DIM, postpartum diseases, herd size) was recorded. Using receiver operator
characteristic curve analyses, blood BHBA thresholds were determined for the
occurrence of metritis, mastitis, clinical ketosis, displaced abomasum, and
lameness. Multivariate binary logistic regression models were built for each
disease, considering cow as the experimental unit and herd as a random effect.
Overall prevalence of SCK (i.e., blood BHBA ≥ 1.2 mmol/L) within 10 countries
was 21.8%, ranging from 11.2 to 36.6%. Cows with SCK had 1.5, 9.5, and 5.0
times greater odds of developing metritis, clinical ketosis, and displaced
abomasum, respectively. Multivariate binary logistic regression models
demonstrated that cows with blood BHBA levels of ≥ 1.4, ≥ 1.1 and ≥ 1.7 mmol/L
during 2 to 15 DIM had 1.7, 10.5, and 6.9 times greater odds of developing
metritis, clinical ketosis, and displaced abomasum, respectively, compared
with cows with lower BHBA blood levels. Interestingly, a postpartum blood BHBA
threshold ≥ 1.1 mmol/L increased the odds for lameness in dairy cows 1.8 (95%
confidence interval: 1.3 to 2.5) times. Overall, prevalence of SCK was high
between 2 to 15 DIM and SCK increased the odds of metritis, clinical ketosis,
lameness, and displaced abomasum in European dairy herds
High temperature dielectric properties of Apical, Kapton, Peek, Teflon AF, and Upilex polymers
Reliable lightweight systems capable of providing electrical power at the magawatt level are a requirement for future manned space exploration missions. This can be achieved by the development of high temperature insulating materials which are not only capable of surviving the hostile space environment but can contribute to reducing the mass and weight of the heat rejection system. In this work, Apical, Upilex, Kapton, Teflon AF, and Peek polymers are characterized for AC and DC dielectric breakdown in air and in silicone oil at temperatures up to 250 C. The materials are also tested in terms of their dielectric constant and dissipation factor at high temperatures with an electrical stress of 60 Hz, 200 V/mil present. The effects of thermal aging on the properties of the films are determined after 15 hours of exposure to 200 and 250 C, each. The results obtained are discussed and conclusions are made concerning the suitability of these dielectrics for use in capacitors and cable insulations in high temperature environments
Endogenous and exogenous progesterone influence body temperature in dairy cows
Three experiments were conducted to determine the effect of endogenous
progesterone (P4) on body temperature comparing lactating, pregnant with
lactating, nonpregnant cows, and to study the effect of exogenous P4
administered via a controlled internal drug release (CIDR) insert on body
temperature in lactating dairy cows. Body temperature was measured vaginally
and rectally using temperature loggers and a digital thermometer,
respectively. In experiment 1, 10 cyclic lactating cows (3 primiparous, 7
multiparous) and 10 lactating, pregnant cows (3 primiparous, 7 multiparous)
were included. Vaginal temperatures and serum P4 concentrations were greater
in pregnant cows (vaginal: 0.3±0.01°C; P4: 5.5±0.4 ng/mL) compared with
nonpregnant cows. In experiment 2, estrous cycles of 14 postpartum healthy,
cyclic, lactating cows (10 primiparous, 4 multiparous) were synchronized, and
cows were assigned randomly to 1 of 2 treatments (CIDR-P4 or CIDR-blank). A
temperature logger was inserted 1 d after ovulation using a P4-free CIDR
(CIDR-blank) and a CIDR containing 1.38g of P4 (CIDR-P4) in the control (n=7)
and the P4-treated group (n=7), respectively. On d 3 after P4 treatment,
vaginal temperature was 0.3±0.03°C greater compared with that on d 1 and d 5.
In experiment 3, 9 cyclic multiparous lactating cows were enrolled 1±1 d after
confirmed ovulation and a temperature logger inserted. Two days later, a
CIDR-P4 was inserted on top of the CIDR-blank. On d 5±1 and d 7±1,
respectively, the CIDR-P4 and CIDR-blank with the temperature logger were
removed. During the CIDR-P4 treatment (48h), vaginal temperature was
0.2±0.05°C and 0.1±0.05°C greater than during the pre- and post-treatment
periods (48h), respectively. Serum P4 concentration peaked during CIDR-P4
treatment (2.2±0.8 ng/mL) and was greater than during the pre-treatment period
(0.2±0.2 ng/mL) for 48h. An increase in vaginal temperature could be due to
endogenous and exogenous P4. However, a correlation between serum P4
concentrations and body temperature did not exist. Further investigations are
warranted to better understand the pathways of the thermogenic effect of P4 on
body temperature
Body temperature around induced estrus in dairy cows
The overall objective of this study was to study the influence of induced
estrus on body temperature, comparing 5 distinct intervals around induced
estrus and to determine the diurnal pattern from 4 ± 1 d before to 4 ± 1 d
after induced estrus. Sixteen estrous cycles of 9 postpartum dairy cows were
synchronized with 2 injections of PGF(2α), 10 d apart. After the second
PGF(2α) injection on d 10, temperature loggers were inserted into the vaginal
cavity for a 12 ± 1-d period. Two days later, a third dose of PGF(2α) was
injected to induce estrus. After confirmation of a corpus luteum, loggers were
removed on d 5 ± 1. Observation of estrus, rectal palpation, and ultrasound
scanning to determine ovulation were carried out every 4 ± 1h, beginning at
12h after the third PGF(2α) injection. Blood samples from the vena coccygea
mediana were collected twice daily from d 11 to 12 and every 4 ± 1h after the
third PGF(2α) injection until ovulation. Vaginal temperature was recorded
every 5 min and averaged to hourly means for the following 5 periods: 1) 48 h
preceding the third PGF(2α) injection, 2) from the third PGF(2α) injection to
first signs of estrus, 3) estrus to ovulation, 4) a 4-h interval in which
ovulation occurred, and 5) a 96-h post-ovulation period. High body
temperatures (39.0 ± 0.5 °C) and low progesterone (P4) concentrations (<0.5
ng/mL) were observed during estrus, whereas low body temperatures were
observed from PGF(2α) injection to estrus (38.6 ± 0.3 °C) and around ovulation
(38.5 ± 0.2 °C), respectively. An association between body temperature and
serum P4 concentrations did not exist. However, P4 concentrations on d 11 and
12 were high (5.0 ± 1.5 ng/mL) and decreased (0.9 ± 0.2 ng/mL) after
ovulation. Diurnal temperature rhythms were similar before and after estrus.
Vaginal temperature before estrus (d 11 and 12) was slightly (0.1 °C) higher
compared with the post-ovulation period
Defluoridation of Ground Water Using Activated Carbon of Ber (Indian Jujube) Leaves
The present study deals with defluoridation of ground water using activated carbon of ber (Indian jujube) leaves. In this study, Activated Ber leaves carbon (ABLC) prepared by heating the leaves in electric furnace was found to be useful for the removal of fluoride. Batch experiments were applied on water sample to study the influence of pH, adsorbent dose and contact time on adsorption efficiency. Fluoride removal reached a maximum of 72.5% by particle size 0.3mm of ABLC at pH 6.0. The adsorption of fluoride from aqueous solution with ABLC followed Freundlich equation. The values of adsorption capacity (K) and intensity of adsorption (1/n) indicate greater affinity for fluoride. Thermally activated Ber leaves carbon (ABLC) was good adsorbent
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Metabolic Perturbations Associated with both PFAS Exposure and Perinatal/Antenatal Depression in Pregnant Individuals: A Meet-in-the-Middle Scoping Review
Purpose of reviewDepression during the perinatal or antenatal period affects at least 1 in 10 women worldwide, with long term health implications for the mother and child. Concurrently, there is increasing evidence associating maternal exposure to per- and poly-fluoroalkyl substances (PFAS) to adverse pregnancy outcomes. We reviewed the body of evidence examining both the associations between PFAS exposure and perturbations in the maternal metabolome, and the associations between the maternal metabolome and perinatal/antenatal depression. Through this, we sought to explore existing evidence of the perinatal metabolome as a potential mediation pathway linking PFAS exposure and perinatal/antenatal depression.Recent findingsThere are few studies examining the metabolomics of PFAS exposure-specifically in pregnant women-and the metabolomics of perinatal/antenatal depression, let alone studies examining both simultaneously. Of the studies reviewed (N = 11), the majority were cross sectional, based outside of the US, and conducted on largely homogenous populations. Our review identified 23 metabolic pathways in the perinatal metabolome common to both PFAS exposure and perinatal/antenatal depression. Future studies may consider findings from our review to conduct literature-derived hypothesis testing focusing on fatty acid metabolism, alanine metabolism, glutamate metabolism, and tyrosine metabolism when exploring the biochemical mechanisms conferring the risk of perinatal/antenatal depression due to PFAS exposure. We recommend that researchers also utilize heterogenous populations, longitudinal study designs, and mediation approaches to elucidate key pathways linking PFAS exposures to perinatal/antenatal depression
Compassionate use of remdesivir in pregnancy: a case series
Coronavirus disease 2019 (COVID-19) has resulted in an unprecedented global healthcare crisis. One special population that poses a challenge is pregnant women with COVID-19. However, there is limited data on treatment options for severe coronavirus disease in pregnancy. Remdesivir, an antiviral drug, is currently being studied as a potential treatment of COVID-19 pneumonia. Nevertheless, pregnant women are also being excluded from various clinical trials for the disease. There are some studies mentioned in the literature which have shown no adverse effects of remdesivir during pregnancy. In this study, we present four serial cases of COVID-19 in pregnant women with moderate to severe symptoms who were treated with remdesivir. All of the them showed positive fetal outcome without any birth defects or malformations. However, further studies are necessary to evaluate the biosafety and effects of remdesivir in pregnant women
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