Development of Paramphistomum sukari Dinnik, 1954 (Trematoda: Paramphistomidae) in a snail host

Parasitology ◽  
1957 ◽  
Vol 47 (1-2) ◽  
pp. 209-216 ◽  
Author(s):  
J. A. Dinnik ◽  
N. N. Dinnik
Keyword(s):  
Intermediate Host ◽  
First Generation ◽  
Second Generation ◽  
Infected Snail ◽  
Snail Host ◽  
Second Phase ◽  
Long Time ◽  
Two Phases ◽  
Successive Generations ◽  
First And Second Generation

The development of Paramphistomum sukari Dinnik in a snail host is described with the emphasis laid on the succession of redial generation.The sporocyst gives birth to about twenty to thirty rediae. These rediae of the first generation commence with the production of daughter rediae then enter the second phase of their productivity during which they produce cercariae. The daughter rediae, or the rediae of the second generation, repeat these two phases during their lives, commencing with redial production and after that changing to the production to cercariae. Both the first- and second-generation rediae are able to produce a few daughter rediae at the end of their life. There is evidence that the subsequent generations of rediae are also able to give birth to daughter rediae and cercariae.As a result the successive generations of rediae maintain the infection in an intermediate host for a long time, probably as long as the infected snail can survive.

The life cycle of Paramphistomum microbothrium Fischoeder, 1901 (Trematoda, Paramphistomidae)

Parasitology ◽  
1954 ◽  
Vol 44 (3-4) ◽  
pp. 285-299 ◽  
Author(s):  
J. A. Dinnik ◽  
N. N. Dinnik
Keyword(s):  
Life Cycle ◽  
Life Span ◽  
Intermediate Host ◽  
East Africa ◽  
Laboratory Experiments ◽  
First Generation ◽  
Infected Snail ◽  
Successive Generations ◽  
Whole Life Cycle ◽  
Further Development

The whole life cycle of Paramphistomum microbothrium Fischoeder, 1901, found in cattle of Kenya, East Africa, has been established experimentally.In laboratory conditions, the eggs hatched miracidia on the 14th to 16th day, if they were kept in water at a temperature of 26–28° C.In a snail, Bulinus alluaudi (Dautzenberg), kept at the temperature of 18–20° C., the miracidium developed into a sporocyst, the elongated body of which, containing young rediae, reached a length of 3·6 mm. in about 2 weeks.The first rediae which emerged from a sporocyst were observed on the 14th day, and on the 20th day the first generation rediae began to produce second-generation rediae. From the 28th day onward the first-generation parent rediae ceased to produce daughter rediae and began to develop cercariae only. This period of production of cercariae by the redia lasted about 30 days, and when the life of the first-generation rediae drew to its close, the old rediae developed a few daughter rediae again.Cercariae began to emerge from the first-generation rediae 30 days after exposure of the snail to miracidia. The cercariae left the parent redia in a very immature state and further development occurred in the liver of the snail. The emergence of cercariae from the infected snail began on the 43rd day after exposure to miracidia. Shortly after emerging from the snail, the cercariae attached themselves to vegetation and encysted.Development of rediae of the second, third, fourth and apparently more successive generations followed an identical course to that outlined for the rediae of the first generation. As a result the successive generations of rediae maintain the infection going in an intermediate host and the infected snails were continually shedding cercariae as long as they lived. In the laboratory experiments the life span of some of the infected snails exceeded a year.In cattle infected experimentally P. microbothrium reached maturity and began passing out the eggs about a 100 days after the encysted cercariae were fed to the animals.

Assimilation of the Puerto Ricans on the Mainland

1968 ◽  
Vol 2 (2) ◽  
pp. 21-39
Author(s):  
John J. Macisco
Keyword(s):  
United States ◽  
First Generation ◽  
Second Generation ◽  
Puerto Ricans ◽  
The United States ◽  
Social Scientists ◽  
First Marriage ◽  
Labor Force Status ◽  
Age At First Marriage ◽  
First And Second Generation

Social scientists have repeatedly tried to specify the process whereby assimilation takes place. This article points out the value of socio-demographic analysis in the study of assimilation, by describing the characteristics of Puerto Ricans on the United States mainland. In order to assess the direction of change between the first and second generation Puerto Ricans, data for the total United States population are also presented. Most of the data are drawn from the 1960 Census. First generation Puerto Ricans are compared with the second generation along the following dimensions: age, education, labor force status, income, occupation, age at first marriage, percent outgroup marriage and fertility. The Author concludes that second generation Puerto Ricans are moving in the direction of total United States averages.

scholarly journals Self-Adaptive K-Means Based on a Covering Algorithm

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Yiwen Zhang ◽  
Yuanyuan Zhou ◽  
Xing Guo ◽  
Jintao Wu ◽  
Qiang He ◽  
...  
Keyword(s):  
Large Scale ◽  
Clustering Algorithm ◽  
Real Data ◽  
Second Phase ◽  
Data Sets ◽  
Number Of Clusters ◽  
Large Scale Data ◽  
Long Time ◽  
Two Phases ◽  
Selection Of

The K-means algorithm is one of the ten classic algorithms in the area of data mining and has been studied by researchers in numerous fields for a long time. However, the value of the clustering number k in the K-means algorithm is not always easy to be determined, and the selection of the initial centers is vulnerable to outliers. This paper proposes an improved K-means clustering algorithm called the covering K-means algorithm (C-K-means). The C-K-means algorithm can not only acquire efficient and accurate clustering results but also self-adaptively provide a reasonable numbers of clusters based on the data features. It includes two phases: the initialization of the covering algorithm (CA) and the Lloyd iteration of the K-means. The first phase executes the CA. CA self-organizes and recognizes the number of clusters k based on the similarities in the data, and it requires neither the number of clusters to be prespecified nor the initial centers to be manually selected. Therefore, it has a “blind” feature, that is, k is not preselected. The second phase performs the Lloyd iteration based on the results of the first phase. The C-K-means algorithm combines the advantages of CA and K-means. Experiments are carried out on the Spark platform, and the results verify the good scalability of the C-K-means algorithm. This algorithm can effectively solve the problem of large-scale data clustering. Extensive experiments on real data sets show that the accuracy and efficiency of the C-K-means algorithm outperforms the existing algorithms under both sequential and parallel conditions.

scholarly journals Why do first and second-generation young migrants volunteer? The Migrant Volunteerism Motivation Model (MVMM)

2019 ◽  
Vol 7 (2) ◽  
pp. 1089-1107 ◽  
Author(s):  
Sara Alfieri ◽  
Daniela Marzana ◽  
Sara Martinez Damia
Keyword(s):  
Transition To Adulthood ◽  
Process Model ◽  
First Generation ◽  
Second Generation ◽  
Maintenance Phase ◽  
Structured Interviews ◽  
Sub Saharan ◽  
Italian Context ◽  
First And Second Generation ◽  
Motivation Model

The following study aims at inquiring into the motivations behind young migrants’ volunteerism in civic organizations in Italy, namely in starting and maintaining their engagement (preliminary vs. maintenance phase). The term “young migrants” refers to first and second generation of migrants who deal with two challenges: the transition to adulthood and the acquisition of a cultural identity. We conducted semi-structured interviews with 37 Sub-Saharan young migrants living in Italy (18-32 years old), 19 of first generation (1G) and 18 of second generation (2G). The Omoto and Snyder’s Volunteer Process Model (VPM, 1995) was used as an underpinning theoretical framework and a guide for the interpretations of the results. The findings indicate that a) motivations included in the VPM are also found for young migrants, b) some of these motivations take particular meaning for young migrants, c) some motivations are not included in the VPM and are specific of this sample. We named these last motivations: social norms, advocacy and ethno-cultural. In addition, some considerations may be advanced regarding the generation and the phase of motivation: 1G migrants are particularly moved by the importance of integration in the Italian context and by the promotion of their ethnic group while 2G migrants reported mostly the desire to understand their roots. The values, the concern for the community and the longing to develop relationships are the motivations for which all young migrants continue to volunteer; however, 1G migrants are also sustained by advocacy and ethno-cultural motivations. Implications and future directions are discussed.

scholarly journals The performance and genetic variation of first and second generation tropical alfalfa (Medicago sativa)

2021 ◽  
Vol 22 (6) ◽  
Author(s):  
Bambang Suwignyo ◽  
LUKMANA ARIFIN ◽  
NAFIATUL UMAMI ◽  
MUHLISIN MUHLISIN ◽  
BAMBANG SUHARTANTO
Keyword(s):  
Organic Matter ◽  
Genetic Variation ◽  
Medicago Sativa ◽  
Crude Protein ◽  
Dry Matter ◽  
First Generation ◽  
Second Generation ◽  
Seed Viability ◽  
Nutrient Content ◽  
First And Second Generation

Abstract. Suwignyo B, Arifin L, Umami N, Muhlisin, Suhartanto B. 2021. The performance and genetic variation of first and second generation tropical alfalfa (Medicago sativa). Biodiversitas 22: 3265-3270. This study aimed to compare the growth performance, nutrient content, seed viability, and genetic variation of first- and second-generation alfalfa (Medicago sativa L.). First and second-generation alfalfa seeds were obtained from the Forage and Pasture Science Laboratory, Department of Animal Nutrition and Feed Science, Faculty of Animal Science, Universitas Gadjah Mada (UGM), Yogyakarta, Indonesia. First generation alfalfa (F1) seeds were obtained from cross breeding of two different parental alfalfa varieties, namely, Canadian and local. The second-generation (F2) seeds were obtained from plants of the first-generation alfalfa (F1). A randomized design experiment was conducted using the two types of alfalfa (first- and second generation). Alfalfa from Canada as female parent was used as the baseline in the genetic masker test. Seeds were planted in a polybag, watered twice a day, and received 12 hours of daylight and 4 hours of artificial light. Plants were then harvested 8 weeks after planting by cutting the plant canopy. Genetic variation was examined using the Inter Simple Sequence Repeat (ISSR) method followed by descriptive analysis. Germination, plant height, dry matter content, organic matter, and crude protein were assessed as variables using a Student’s T-test. Our results showed that germination, plant height, leaf color, and nutrient content (dry matter, organic matter, and crude protein) of the first- and second-generation alfalfa plants were not significantly different. However, the second-generation alfalfa demonstrated better seed viability than the first generation plants, then it can be categorized as a new genotype (tropical alfalfa) based on genetic variation analysis.

Differential Impairments in Incentive Learning Caused by First‐ and Second‐ Generation Antipsychotic Drugs

2016 ◽  
Author(s):  
Matthew Florczynski
Keyword(s):  
Neural Control ◽  
First Generation ◽  
Antipsychotic Drugs ◽  
Second Generation ◽  
Operant Chamber ◽  
Incentive Learning ◽  
Dopamine Receptor Antagonists ◽  
Natural Response ◽  
Second Generation Antipsychotic ◽  
First And Second Generation

Schizophrenia is a neuropsychiatric disorder characterized by increased function of dopamine in the brain.  Dopamine release is a natural response to reward.  It promotes incentive learning (IL), a process by which neutral stimuli acquire the ability to elicit approach and other responses.  A recent model characterizes dopamine‐mediated IL as a progressive process with early and late stages accompanied by a shift in neural control from the nucleus accumbens (NAc) to the dorsolateral striatum (DLS).  A parallel can be drawn to differences in regionally specific neural responses generated by first‐ and second‐generation antipsychotic drugs (APDs) used to treat schizophrenia.  APDs are dopamine receptor antagonists, but first‐generation APDs affect the NAc and DLS while second‐generation APDs affect primarily the NAc.  We compared the effects of APDs on IL. Rats (N = 48) were trained to press a lever forfood pellets in an operant chamber.  Intraperitoneal injections (1 hr before testing) of the first‐generation APD haloperidol (0,0.05,0.10,0.20 mg/kg) or of the second‐generation APD risperidone (0,0.20,0.40,0.80 mg/kg) induced dose‐dependent suppression of lever pressing on days 1‐4, with the highest dose groups failing to demonstrate any evidence of previous learning on day 5 when tested drug‐free.  On days 16‐20 haloperidol induced a day‐to‐day suppression not seen with risperidone.  The results suggest that the effects of first‐ and second‐generation APDs on learning processes putatively mediated by the NAc and DLS can be differentiated experimentally.  The findings imply that APDs may differentially affect IL inpatients with schizophrenia.  

4.  Differential Impairments in Incentive Learning Caused by First‐ and Second‐ Generation Antipsychotic Drugs

2016 ◽  
Author(s):  
Matthew Florczynski
Keyword(s):  
Neural Control ◽  
First Generation ◽  
Antipsychotic Drugs ◽  
Second Generation ◽  
Operant Chamber ◽  
Incentive Learning ◽  
Dopamine Receptor Antagonists ◽  
Natural Response ◽  
Second Generation Antipsychotic ◽  
First And Second Generation

Schizophrenia is a neuropsychiatric disorder characterized by increased function of dopamine in the brain.  Dopamine release is a natural response to reward.  It promotes incentive learning (IL), a process by which neutral stimuli acquire the ability to elicit approach and other responses.  A recent model characterizes dopamine‐mediated IL as a progressive process with early and late stages accompanied by a shift in neural control from the nucleus accumbens (NAc) to the dorsolateral striatum (DLS).  A parallel can be drawn to differences in regionally specific neural responses generated by first‐ and second‐generation antipsychotic drugs (APDs) used to treat schizophrenia.  APDs are dopamine receptor antagonists, but first‐generation APDs affect the NAc and DLS while second‐generation APDs affect primarily the NAc.  We compared the effects of APDs on IL. Rats (N = 48) were trained to press a lever for food pellets in an operant chamber.  Intraperitoneal injections (1 hr before testing) of the first‐generation APD haloperidol (0,0.05,0.10,0.20 mg/kg) or of the second‐generation APD risperidone (0,0.20,0.40,0.80 mg/kg) induced dose‐dependent suppression of lever pressing on days 1‐4, with the highest dose groups failing to demonstrate any evidence of previous learning on day 5 when tested drug‐free.  On days 16‐20, haloperidol induced a day‐to‐day suppression not seen with risperidone.  The results suggest that the effects of first‐ and second‐generation APDs on learning processes putatively mediated by the NAc and DLS can be differentiated experimentally.  The findings imply that APDs may differentially affect IL inpatients with schizophrenia.

Reassessing the Generational Disparity in Immigrant Offending: A Within-family Comparison of Involvement in Crime

2019 ◽  
Vol 56 (6) ◽  
pp. 851-887 ◽  
Author(s):  
Bianca E. Bersani ◽  
Adam W. Pittman
Keyword(s):  
First Generation ◽  
Second Generation ◽  
Well Being ◽  
Foreign Born ◽  
Data Set ◽  
The Difference ◽  
Successive Generations ◽  
Offending Patterns ◽  
High Degree ◽  
Parent Child

Objective:This study reassesses the generational disparity in immigrant offending. Patterns and predictors of offending are compared using traditional peer-based models and an alternative within-family (parent–child dyad) model.Method:The National Longitudinal Survey of Youth (1979; NLSY79) and NLSY-Child and Young Adult (NLSY_CYA) data are merged to create an intergenerational data set to compare generational disparities in immigrant offending across peers and within families. Differences in self-reported offending (prevalence and variety) by immigrant generation are assessed using a combination of descriptive analyses (χ2and analysis of variance) and regression models.Results:While NLSY_CYA children generally are at a greater risk of offending compared with the NLSY79 mothers, the difference in offending is greatest between first-generation mom and second-generation child dyads. Disparities in offending are driven in large part by exceedingly low levels of offending among first-generation immigrants.Conclusion:Although the factors driving an increase in offending between parent–child generations are not unique to immigrants, they are amplified in immigrant families. Whereas the second generation is remarkably similar to their U.S.-born counterparts in terms of their involvement in crime, suggesting a high degree of swift integration, the greater involvement in crime among the children of immigrants compared to their foreign-born mothers suggests a decline in well-being across successive generations.

One person, three identities? Examining re-politicization of ethnic, national, and Australian identities among 1.5-generation Taiwanese immigrants in Australia

2020 ◽  
pp. 144078332093415
Author(s):  
Yao-Tai Li
Keyword(s):  
First Generation ◽  
Second Generation ◽  
Identity Negotiation ◽  
Generation 1.5 ◽  
The Political ◽  
Host Society ◽  
1.5 Generation ◽  
Ethnic Chinese ◽  
Second Generation Immigrants ◽  
First And Second Generation

Immigrants of the 1.5-generation (1.5-ers) differ from first- and second-generation immigrants because they are generally better immersed in the culture of the host society than the first generation; yet, compared to the second generation, they often have to renegotiate their identities in relation to parents, colleagues at work, and people in the host society during the processes of migration. Drawing on interview data from Taiwanese 1.5-ers in Australia, this article takes a further step and points out that in addition to the identity struggle between home and host country, Taiwanese 1.5-ers also identify as ethnic Chinese (Huaren) and constantly negotiate between these three identities (Huaren, Taiwanese, and Australian). This article argues that identity negotiation and hybridization is in nature a re-politicization process in which respondents are fully aware of the political meanings and power disparities of each identity. It is also a process whereby Taiwanese 1.5-ers mobilize, downplay, and hybridize specific identities based on time and context.

scholarly journals Physics-Based Simulations of Flow and Fire Development Downstream of a Canopy

Atmosphere ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 683
Author(s):  
Gilbert Accary ◽  
Duncan Sutherland ◽  
Nicolas Frangieh ◽  
Khalid Moinuddin ◽  
Ibrahim Shamseddine ◽  
...  
Keyword(s):  
Turbulent Flow ◽  
Forest Canopy ◽  
Prescribed Burning ◽  
Second Phase ◽  
Flow Conditions ◽  
Developed Turbulence ◽  
Large Eddy ◽  
Long Time ◽  
Two Phases ◽  
The Impact

The behavior of a grassland fire propagating downstream of a forest canopy has been simulated numerically using the fully physics-based wildfire model FIRESTAR3D. This configuration reproduces quite accurately the situation encountered when a wildfire spreads from a forest to an open grassland, as can be the case in a fuel break or a clearing, or during a prescribed burning operation. One of the objectives of this study was to evaluate the impact of the presence of a canopy upstream of a grassfire, especially the modifications of the local wind conditions before and inside a clearing or a fuel break. The knowledge of this kind of information constitutes a major element in improving the safety conditions of forest managers and firefighters in charge of firefighting or prescribed burning operations in such configurations. Another objective was to study the behavior of the fire under realistic turbulent flow conditions, i.e., flow resulting from the interaction between an atmospheric boundary layer (ABL) with a surrounding canopy. Therefore, the study was divided into two phases. The first phase consisted of generating an ABL/canopy turbulent flow above a pine forest (10 m high, 200 m long) using periodic boundary conditions along the streamwise direction. Large Eddy Simulations (LES) were carried out for a sufficiently long time to achieve a quasi-fully developed turbulence. The second phase consisted of simulating the propagation of a surface fire through a grassland, bordered upstream by a forest section (having the same characteristics used for the first step), while imposing the turbulent flow obtained from the first step as a dynamic inlet condition to the domain. The simulations were carried out for a wind speed that ranged between 1 and 12 m/s; these values have allowed the simulations to cover the two regimes of propagation of surfaces fires, namely plume-dominated and wind-driven fires.

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