Invasive ‘Devil Fish’ Plague Mexico’s Waters. Can’t Beat ‘Em? Eat ‘Em

October 19, 2017

In trying to get people to eat the Pez Diablo, or suckermouth catfish, sustainable fisheries specialist Mike Mitchell says it isn’t “a problem of biology or science, but marketing.”

Pez diablo: “devil fish.” That’s what locals in the Mexican state of Tabasco call the armored catfish that has invaded their waters.

Also known as suckermouths, the species is popular with aquarium owners because the fish eats the algae that pollute tanks. But in the wild, that same behavior erodes shorelines and devastates underwater plant life.

A Mexican social enterprise called Acari is trying to do something about it — by creating a taste for these aquatic terrors.

Francisco Mendoza, a 38-year-old fisherman from the village of Simón Sarlat in Tabasco, has fished in the region’s lagoons and streams since he was 15.

“We didn’t even know the fish before,” Mendoza says. Róbalo, or snook, used to be abundant. Those are nearly gone, their marshy habitat taken over by the invasive pez diablo.

A fish that’s a survivor

No one knows for sure how suckermouths became such a problem, but they now plague Texas, Florida and southern Mexico. It may be the “Nemo effect” — that fish prized for cleaning aquariums grew too big for their tanks and were set free in the wild. Others believe that aquaculture facilities inadvertently released them. It’s likely a combination. But once in the waterways, their population exploded. The pez diablo matures rapidly, lays 500 eggs at a time and lives seven to 15 years. It is encased in hard scales, and can breathe outside water for up to four hours. In other words, it is a survivor.

Sustainable fisheries specialist Mike Mitchell also grew up fishing, and when he took an environmental science class in high school, something clicked. Learning about the efficiency of producing fish compared to other animal sources of protein, “I saw the viability of fish to feed the world’s population,” he says.

So, in 2014, with a degree from the University of Pennsylvania and several years of working in Latin America under his belt, Mitchell applied for a Fulbright research grant with a proposal to analyze freshwater fishing in Mexico. When he started his research in Tabasco, he talked with countless fishermen, who kept asking: “What the heck am I going to do with the pez diablo?”

Mitchell checked out what was already known about the fish, particularly the research of Salomón Páramo-Delgadillo of the University Juárez Autónoma de Tabasco (UJAT). Mitchell’s first plan of attack was to turn the pez diablo into fish meal. He says that effort turned out to be “incredibly tedious, low yield, and not sustainable.”

Plan B was to eat the fish. “I thought about Chilean sea bass,” Mitchell says. “It used to be called the Patagonian toothfish, and it’s a slimy creature.” But, rebranded, Chilean sea bass became a delicacy, found on the menus of upscale restaurants around the globe.

Locals believed the pez diablo to be poisonous, but Páramo-Delgadillo’s research verified that is not the case. “Salomón showed me how to fillet the fish, so I did a couple of taste tests with other junior researchers in the lab,” Mitchell said.

The flavor is similar to other mild freshwater fish. “It wasn’t a problem of biology or science, but marketing,” Mitchell eventually concluded. “Let’s not reinvent the wheel. Let’s just fillet it, change the name and call it a day.”

Easier said than done

“It has been incredibly difficult,” Mitchell admits. He refers to the fish as acari, the name used in its native Brazil, but others keep calling it pez diablo. Getting people to cook it was as difficult as convincing them to call it acari. It would take more than a couple of university researchers to sway public opinion.

It wasn’t until Mitchell sat down with chef Lupita Vidal that he found a taker.

Vidal and her husband, photographer Jesus David, own La Cevichería Tabasco, a restaurant in the state’s capital of Villahermosa. The eatery is more than just a business for them.

“We believe that through gastronomy and art, great social changes can be generated,” Vidal says. On the menu are ceviches, tacos, tostadas and seafood plates, all of them sourced locally. “More than just filling bellies and hearts, my dishes have a cause and a conscience.”

Vidal developed a fish burger of pez diablo and in May 2016 added it to her menu. “There were people who wrote us on social media saying that they would never return to our restaurant because we served that species. But together with Mike, we believe that it is just a matter of time, patience and perseverance for this fish to be accepted.”

With his first buyer lined up, Mitchell officially established Acari, which he describes as a small business that applies a market-driven approach to improving both the environment and the well-being of fishermen and others in the region.

At the start, Vidal sold one fish burger per week. Now customers order 15 or 20 in the same amount of time. The fish is as nutritious as it is delicious, packed with protein and omega 3 fatty acids.

Victor Hernandez was one of the initial non-believers. Now a third-year biology student at UJAT, he attended one of Mitchell’s workshops on the pez diablo. He says, “My family fished in the rivers, and were always talking about the pez diablo. I thought, ‘I have to get involved!'” He joined forces with Mitchell, but still hesitated when tasting time arrived.

“I hadn’t eaten the fish before. I was the last one — I didn’t want to try it,” Hernandez says. “Then I tasted the fish burger and … wow! It was súper rico.” Totally delicious.

However, it will take a lot more than 20 burgers a week to make a dent in the pez diablo problem. Since founding Acari, they’ve sold around 450 kilos of fish fillets. The yield of fillet is only about 20 percent per fish, meaning that Acari has removed roughly 2,500 kilos of fish from local waters. Although the local government is supporting Acari’s efforts, the stigma of the fish remains high, and Vidal remains the only chef in Tabasco offering pez diablo on the menu. Acari has had more success outside of the state: It currently supplies two more restaurants, and as of this month has begun deliveries to Google in Mexico City.

In addition to finding corporate customers, Acari hopes to help some of the most marginalized in the community through donations of the fish. An estimated 450,000 migrants and refugees enter Mexico from Central America every year, fleeing violence in their home countries. Acari developed fish croquettes to donate to the migrants, but soon realized that a shelf-stable product would be more useful. They are now perfecting a fish jerky.

And rather than outsourcing production, fishermen like Mendoza have been taught to fillet and package the fish, earning around double what they used to take in for fishing alone. According to Mendoza, the pez diablo “might be a plague, but for us it is an economic benefit.”

The fish is a devil of a problem. But Acari looks poised to outwit it.
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Messi emulates Ronaldo with 100th European goal

Lionel Messi’s effort against Olympiacos on Wednesday makes him the second player after Cristiano Ronaldo to reach a century of goals in UEFA club competition.
©Getty Images

Lionel Messi has become the second player to reach 100 goals in UEFA club competition, taking 21 fewer matches than Cristiano Ronaldo, who achieved the feat in April.

His tally comprises 97 strikes in the UEFA Champions League and three in the UEFA Super Cup, and came in just 122 games. Messi opened his account against Panathinaikos on 2 November 2005 and got to 50 when he scored five against Bayer Leverkusen in the round of 16 on 7 March 2012. The next-highest non-European player is Didier Drogba on 50.

Most goals in UEFA club competition (*still active)
113 – Cristiano Ronaldo* (151 games)
100 – Lionel Messi* (122)
76 – Raúl González (158)
70 – Filippo Inzaghi (114)
67 – Andriy Shevchenko (142)
62 – Ruud van Nistelrooy (92)
61 – Gerd Müller (69)
59 – Thierry Henry (140)
59 – Henrik Larsson (108)
56 – Zlatan Ibrahimović* (139)
54 – Eusébio (70)
53 – Alessandro Del Piero (129)
51 – Karim Benzema* (99)
50 – Sergio Agüero* (86)
50 – Didier Drogba (102)
50 – Klaas-Jan Huntelaar* (87)

Statistics include qualifying and competition proper for the European Cup (including the UEFA Champions League), UEFA Cup/UEFA Europa League, UEFA Super Cup and UEFA Intertoto Cup.

Buhari and the stigma of sectionalism

The reformist inclination of President Muhammadu Buhari has never been helped by what has become an historical perception of sectionalism in the direction of his leadership. The damage was done during his leadership debut between December 1983 and August 1985 when key southern politicians and opinion moulders assumed he favoured the North at the expense of the South. Prof. Wole Soyinka indicted Buhari’s approach to governance as being “triple standard”, while it is on record that Gen. Alani Akinrinade and Brig. Benjamin Adekunle, two veterans of the civil war, equally voiced their disapproval. Both Adekunle and Akinrinade would later advocate the rather retrogressive confederal system of government as their preferred option, something this writer referred to as a serious indictment of the then Buhari regime considering the fact that confederation was what was advocated by those on the other side of the Nigerian conflict.

But President Buhari has integrity in many other respects, which was why most of those who had opposed his leadership style between 1983 and 1985, Soyinka and Akinrinade inclusive, came out rooting for him in 2015. This writer was once one critic who would later become an admirer of Buhari upon observing his simplicity while at Oxford to give a talk. It was an impressive display of patriotism on that occasion. When doctored opinion polls projected erstwhile President Goodluck Jonathan as the likely candidate to win the 2015 presidential extension, I wrote to say it would be Buhari based on research.

Relatively, President Buhari has not been disappointing. He would seem to have handled the Boko Haram insurgency much better than his predecessor. Many Nigerians would not have known the extent of the looting of the Nigerian treasury by the treasurers but for his inquisitiveness with our patrimony. Not many would have known that a minister was in a position to buy 56 exotic houses in less than four years, and not many would have known that millions of dollars could be concealed in uncompleted buildings. The wife, Aisha, has been an epitome of decency, not prone to the type of crudity observed in the past.

But this spectre of favouritism continues to taint Buhari. There have been issues of lopsidedness in his appointments and the sidetracking of those who supported his election. Such has been the perception of sectionalism on the part of President Buhari that his critics would assume he was shielding those herdsmen whose barbarism has led to many deaths in various states of the federation. He would not even be given the benefit of the doubt in the current allegation that he had requested the President of the World Bank to focus on the “northern regions” in its developmental activities in Nigeria. However, appreciating the gravity of the allegation, the Presidency has tried to explain that the request was made for the North-Eastern zone severely ravaged by the Boko Haram insurgency. Even if all he did was make a denial, it is important if the objection of Nigerians to sectionalism has been acknowledged.

Ordinarily, a request for development to be focused on the North would have been considered patriotic on the part of any leader that seeks a balanced and evenly developed Nigerian federation. The North is behind the South and the genesis is the dual approach to education during the colonial era. The South would equally have been backward, were it not for those missionaries – Anglican, Baptist, Catholic, Methodist, etc-who established numerous schools. The interventions of the regional governments were at the level of policy formulation. For instance, in the defunct Western Region, the compulsory and free education policy of the Obafemi Awolowo-led Action Group worked well for all. State governments in the North must learn to focus on the education of the citizenry and de-emphasise distractions such as the sponsorship of mass marriages for those who should still be at school. The Danjumas and the Dangotes can also do for the North what the likes of Ford Foundation did for posterity.

All said, many would still vote for Buhari if he were physically strong enough to seek re-election in 2019. However, he would urgently need to re-appraise his leadership style and douse those negative perceptions, and this should not be for the short term opportunism of winning an election but for the sake of his place in the history of our great nation.

–Dr. Anthony Akinola, Oxford, United Kingdom

N-power 2017 questions and Anwers

Database: The Client-Server Database
Exercise: The Client-Server Database – General Questions
1. Which of the following statements is true about symmetric multiprocessing?
A.
A single copy of the operating system resides in each processor.
B.
Useful for situations where data must remain in memory to process.
C.
Bottlenecks increase with uniprocessor systems because tasks are not shared.
D.
The problems of memory contention are unlikely.
Answer: Option B
Explanation:
________________________________________
2. Which of the following items are not necessary for client/server?
A.
Assure that tools will connect with middleware.
B.
Understand the requirements.
C.
Determine network bandwidth capabilities.
D.
Include the use of a file server.
Answer: Option D
Explanation:
________________________________________
3. A benefit of the three-tier architecture is which of the following?
A.
New modules can be built to support specific business needs
B.
Performance improves for compiled SQL statements
C.
Results in a thinner client and database server
D.
All of the above.
Answer: Option A
________________________________________
4. Which of the following statements is true concerning JDBC?
A.
It is language independent.
B.
It is similar in concept to ODBC.
C.
It is useful for all object-oriented languages.
D.
It consists of three main layers.
Answer: Option B
________________________________________
5. A characteristic of a file server is which of the following?
A.
Manages file operations and is shared on a network.
B.
Manages file operations and is limited to one PC.
C.
Acts as a fat client and is shared on a network.
D.
Acts as a fat client and is limited to one PC.
Answer: Option A
________________________________________
6. Stored procedures have which of the following advantages?
A.
It takes a longer time to write them as compared to writing Visual Basic.
B.
Network traffic increases
C.
Data integrity improves as multiple applications access the same stored procedure.
D.
Result in thicker client and thinner database server.
Answer: Option C
Explanation:
________________________________________
7. Which of the following statements is a true statement concerning the open database connectivity standard (ODBC)?
A.
Each vendor desiring to be ODBC-complaint provides an ODBC driver.
B.
Requires certain criteria to be met in order to establish an ODBC connection.
C.
Provides a programming interface that provides a common language for application programs to access and process SQL databases independent of the RDBMS accessed.
D.
All of the above.
Answer: Option D
________________________________________
8. Which of the following is true concerning QBE?
A.
An official standard has been defined for QBE.
B.
QBE cannot be used for client/server systems.
C.
QBE does not give the programmer a visual programming environment.
D.
Complete applications can be written using QBE.
Answer: Option D
________________________________________
9. Client/server security includes which of the following?
A.
Physical security
B.
Change control security
C.
Measures taken to secure all systems
D.
All of the above.
Answer: Option D
________________________________________
10. An application program interface (API) is which of the following?
A.
The same thing as ODBC.
B.
Middleware that does not provide access to a database.
C.
Middleware that provides access to a database.
D.
The same thing as JDBC.
Answer: Option C
________________________________________
11. Three-tier architecture includes which of the following?
A.
Three server layers
B.
A client layer and two server layers
C.
Two client layers and one server layer
D.
Three client layers
Answer: Option B

12. Which of the following is true concerning the mainframe?
A.
It is the same thing as client/server.
B.
Requires someone to decide which code should be on the workstation or the server.
C.
Mission-critical systems have tended to remain there.
D.
All of the above.
Answer: Option C
________________________________________
13. A server cannot serve on which of the following levels?
A.
Client Layer
B.
Business Layer
C.
Database Layer
D.
All of the above.
Answer: Option A
________________________________________
14. The three different application logic components are which of the following?
A.
Presentation, Client, and Storage
B.
Presentation, Client, and Processing
C.
Presentation, Processing, and Storage
D.
Presentation, Processing, and Network
Answer: Option C
________________________________________
15. A database server is responsible for which of the following?
A.
Database storage
B.
Data processing logic
C.
Data presentation logic
D.
All of the above.
Answer: Option A
16. The DBMS that is most difficult to use is ________ .
A.
Microsoft’s SQL Server
B.
Microsoft’s Access
C.
IBM’s DB2
D.
Oracle Corporation’s Oracle
Answer: Option D

Exercise : Introduction to Database – General Questions
1. The DBMS acts as an interface between what two components of an enterprise-class database system?
A.
Database application and the database
B.
Data and the database
C.
The user and the database application
D.
Database application and SQL
Answer: Option A
________________________________________
2. Which of the following products was an early implementation of the relational model developed by E.F. Codd of IBM?
A.
IDMS
B.
DB2
C.
dBase-II
D.
R:base
Answer: Option B
________________________________________
3. The following are components of a database except ________ .
A.
user data
B.
metadata
C.
reports
D.
indexes
Answer: Option C
________________________________________
4. An application where only one user accesses the database at a given time is an example of a(n) ________ .
A.
single-user database application
B.
multiuser database application
C.
e-commerce database application
D.
data mining database application
Answer: Option A
________________________________________
5. An on-line commercial site such as Amazon.com is an example of a(n) ________ .
A.
single-user database application
B.
multiuser database application
C.
e-commerce database application
D.
data mining database application
Answer: Option C

6. Which of the following products was the first to implement true relational algebra in a PC DBMS?
A.
IDMS
B.
Oracle
C.
dBase-II
D.
R:base
Answer: Option D
________________________________________
7. SQL stands for ________ .
A.
Structured Query Language
B.
Sequential Query Language
C.
Structured Question Language
D.
Sequential Question Language
Answer: Option A
________________________________________
8. Because it contains a description of its own structure, a database is considered to be ________ .
A.
described
B.
metadata compatible
C.
self-describing
D.
an application program
Answer: Option C
________________________________________
9. The following are functions of a DBMS except ________ .
A.
creating and processing forms
B.
creating databases
C.
processing data
D.
administrating databases
Answer: Option A
________________________________________
10. Helping people keep track of things is the purpose of a(n) ________ .
A.
database
B.
table
C.
instance
D.
relationship
Answer: Option A

11. Which of the following products implemented the CODASYL DBTG model?
A.
IDMS
B.
DB2
C.
dBase-II
D.
R:base
Answer: Option A
________________________________________
12. An Enterprise Resource Planning application is an example of a(n) ________ .
A.
single-user database application
B.
multiuser database application
C.
e-commerce database application
D.
data mining database application
Answer: Option B
________________________________________
13. A DBMS that combines a DBMS and an application generator is ________ .
A.
Microsoft’s SQL Server
B.
Microsoft’s Access
C.
IBM’s DB2
D.
Oracle Corporation’s Oracle
Answer: Option B
________________________________________
14. You have run an SQL statement that asked the DBMS to display data in a table named USER_TABLES. The results include columns of data labeled “TableName,” “NumberOfColumns” and “PrimaryKey.” You are looking at ________ .
A.
user data.
B.
metadata
C.
A report
D.
indexes
Answer: Option B
________________________________________
15. Which of the following is not considered to be a basic element of an enterprise-class database system?
A.
Users
B.
Database applications
C.
DBMS
D.
COBOL programs
Answer: Option D
Exercise : The Relational Model and Normalization – General Questions
1. Every time attribute A appears, it is matched with the same value of attribute B, but not the same value of attribute C. Therefore, it is true that:
A.
A → B.
B.
A → C.
C.
A → (B,C).
D.
(B,C) → A.
Answer: Option A
________________________________________
2. The different classes of relations created by the technique for preventing modification anomalies are called:
A.
normal forms.
B.
referential integrity constraints.
C.
functional dependencies.
D.
None of the above is correct.
Answer: Option A
________________________________________
3. A relation is in this form if it is in BCNF and has no multivalued dependencies:
A.
second normal form.
B.
third normal form.
C.
fourth normal form.
D.
domain/key normal form.
Answer: Option C
________________________________________
4. Row is synonymous with the term:
A.
record.
B.
relation.
C.
column.
D.
field.
Answer: Option A
________________________________________
5. The primary key is selected from the:
A.
composite keys.
B.
determinants.
C.
candidate keys.
D.
foreign keys.
Answer: Option C

6. Which of the following is a group of one or more attributes that uniquely identifies a row?
A.
Key
B.
Determinant
C.
Tuple
D.
Relation
Answer: Option A
________________________________________
7. When the values in one or more attributes being used as a foreign key must exist in another set of one or more attributes in another table, we have created a(n):
A.
transitive dependency.
B.
insertion anomaly.
C.
referential integrity constraint.
D.
normal form.
Answer: Option C
________________________________________
8. A relation is considered a:
A.
Column.
B.
one-dimensional table.
C.
two-dimensional table.
D.
three-dimensional table.
Answer: Option C
________________________________________
9. In the relational model, relationships between relations or tables are created by using:
A.
composite keys.
B.
determinants.
C.
candidate keys.
D.
foreign keys.
Answer: Option D
________________________________________
10. A functional dependency is a relationship between or among:
A.
tables.
B.
rows.
C.
relations.
D.
attributes.
Answer: Option D
11. Table is synonymous with the term:
A.
record.
B.
relation.
C.
column.
D.
field.
Answer: Option B
Explanation:
________________________________________
12. Which of the following is not a restriction for a table to be a relation?
A.
The cells of the table must contain a single value.
B.
All of the entries in any column must be of the same kind.
C.
The columns must be ordered.
D.
No two rows in a table may be identical.
View Answer Discuss in Forum Workspace Report

________________________________________
13. For some relations, changing the data can have undesirable consequences called:
A.
referential integrity constraints.
B.
modification anomalies.
C.
normal forms.
D.
transitive dependencies.
Answer: Option B
________________________________________
14. A key:
A.
must always be composed of two or more columns.
B.
can only be one column.
C.
identifies a row.
D.
identifies a column.
Answer: Option C
________________________________________
15. An attribute is a(n):
A.
column of a table.
B.
two dimensional table.
C.
row of a table.
D.
key of a table.
Answer: Option A

11. Table is synonymous with the term:
A.
record.
B.
relation.
C.
column.
D.
field.
Answer: Option B
________________________________________
12. Which of the following is not a restriction for a table to be a relation?
A.
The cells of the table must contain a single value.
B.
All of the entries in any column must be of the same kind.
C.
The columns must be ordered.
D.
No two rows in a table may be identical.
Answer: Option C
________________________________________
13. For some relations, changing the data can have undesirable consequences called:
A.
referential integrity constraints.
B.
modification anomalies.
C.
normal forms.
D.
transitive dependencies.
Answer: Option B
________________________________________
14. A key:
A.
must always be composed of two or more columns.
B.
can only be one column.
C.
identifies a row.
D.
identifies a column.
Answer: Option C
________________________________________
15. An attribute is a(n):
A.
column of a table.
B.
two dimensional table.
C.
row of a table.
D.
key of a table.
Answer: Option A
Exercise: Object-Oriented Data Modeling – General Questions
1. The fact that the same operation may apply to two or more classes is called what?
A.
Inheritance
B.
Polymorphism
C.
Encapsulation
D.
Multiple classification
Answer: Option B
________________________________________
2. The object-oriented development life cycle is which of the following?
A.
Analysis, design, and implementation steps in the given order and using multiple iterations.
B.
Analysis, design, and implementation steps in the given order and going through the steps no more than one time.
C.
Analysis, design, and implementation steps in any order and using multiple iterations.
D.
Analysis, design, and implementation steps in any order and going through the steps no more than one time.
Answer: Option A
________________________________________
3. Multiplicity is the same as what concept for an ERD?
A.
Relationship
B.
Attribute
C.
Entity
D.
Cardinality
Answer: Option D
________________________________________
4. Composition is a stronger form of which of the following?
A.
Aggregation
B.
Encapsulation
C.
Inheritance
D.
All of the above.
Answer: Option A
________________________________________
5. An abstract class is which of the following?
A.
A class that has direct instances, but whose descendants may have direct instances.
B.
A class that has no direct instances, but whose descendants may have direct instances.
C.
A class that has direct instances, but whose descendants may not have direct instances.
D.
A class that has no direct instances, but whose descendants may not have direct instances
Answer: Option B

6. The term Complete for a UML has the same meaning as which of the following for an EER diagram?
A.
Overlapping rule
B.
Disjoint rule
C.
Total specialization rule
D.
Partial specialization rule
Answer: Option C
________________________________________
7. A UML diagram includes which of the following?
A.
Class name
B.
List of attributes
C.
List of operations
D.
All of the above.
Answer: Option D
________________________________________
8. An object can have which of the following multiplicities?
A.
Zero
B.
One
C.
More than one
D.
All of the above.
Answer: Option D
________________________________________
9. Which of the following statement is true concerning objects and/or classes?
A.
An object is an instance of a class.
B.
A class is an instance of an object.
C.
An object includes encapsulates only data.
D.
A class includes encapsulates only data.
Answer: Option A
________________________________________
10. Which of the following applies to a class rather than an object?
A.
Query
B.
Update
C.
Scope
D.
Constructor
Answer: Option C
11. The benefits of object-oriented modeling are which of the following?
A.
The ability to tackle more challenging problems
B.
Reusability of analysis, design, and programming results
C.
Improved communication between users, analysts, etc.
D.
All of the above.
Answer: Option D
________________________________________
12. The term Incomplete for a UML has the same meaning as which of the following for an EER diagram?
A.
Overlapping rule
B.
Disjoint rule
C.
Total specialization rule
D.
Partial specialization rule
Answer: Option D
________________________________________
13. A constructor operation does which of the following?
A.
Creates a new instance of a class
B.
Updates an existing instance of a class
C.
Deletes and existing instance of a class
D.
All of the above.
Answer: Option A
________________________________________
14. Which of the following is a technique for hiding the internal implementation details of an object?
A.
Encapsulation
B.
Polymorphism
C.
Inheritance
D.
All of the above.
Answer: Option A
________________________________________
15. Aggregation is which of the following?
A.
Expresses a part-of relationship and is a stronger form of an association relationship.
B.
Expresses a part-of relationship and is a weaker form of an association relationship.
C.
Expresses an is-a relationship and is a stronger form of an association relationship.
D.
Expresses an is-a relationship and is a weaker form of an association relationship.
Answer: Option A

N-power 2017 questions and Anwers

Database: The Client-Server Database
Exercise: The Client-Server Database – General Questions
1. Which of the following statements is true about symmetric multiprocessing?
A.
A single copy of the operating system resides in each processor.
B.
Useful for situations where data must remain in memory to process.
C.
Bottlenecks increase with uniprocessor systems because tasks are not shared.
D.
The problems of memory contention are unlikely.
Answer: Option B
Explanation:
________________________________________
2. Which of the following items are not necessary for client/server?
A.
Assure that tools will connect with middleware.
B.
Understand the requirements.
C.
Determine network bandwidth capabilities.
D.
Include the use of a file server.
Answer: Option D
Explanation:
________________________________________
3. A benefit of the three-tier architecture is which of the following?
A.
New modules can be built to support specific business needs
B.
Performance improves for compiled SQL statements
C.
Results in a thinner client and database server
D.
All of the above.
Answer: Option A
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4. Which of the following statements is true concerning JDBC?
A.
It is language independent.
B.
It is similar in concept to ODBC.
C.
It is useful for all object-oriented languages.
D.
It consists of three main layers.
Answer: Option B
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5. A characteristic of a file server is which of the following?
A.
Manages file operations and is shared on a network.
B.
Manages file operations and is limited to one PC.
C.
Acts as a fat client and is shared on a network.
D.
Acts as a fat client and is limited to one PC.
Answer: Option A
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6. Stored procedures have which of the following advantages?
A.
It takes a longer time to write them as compared to writing Visual Basic.
B.
Network traffic increases
C.
Data integrity improves as multiple applications access the same stored procedure.
D.
Result in thicker client and thinner database server.
Answer: Option C
Explanation:
________________________________________
7. Which of the following statements is a true statement concerning the open database connectivity standard (ODBC)?
A.
Each vendor desiring to be ODBC-complaint provides an ODBC driver.
B.
Requires certain criteria to be met in order to establish an ODBC connection.
C.
Provides a programming interface that provides a common language for application programs to access and process SQL databases independent of the RDBMS accessed.
D.
All of the above.
Answer: Option D
________________________________________
8. Which of the following is true concerning QBE?
A.
An official standard has been defined for QBE.
B.
QBE cannot be used for client/server systems.
C.
QBE does not give the programmer a visual programming environment.
D.
Complete applications can be written using QBE.
Answer: Option D
________________________________________
9. Client/server security includes which of the following?
A.
Physical security
B.
Change control security
C.
Measures taken to secure all systems
D.
All of the above.
Answer: Option D
________________________________________
10. An application program interface (API) is which of the following?
A.
The same thing as ODBC.
B.
Middleware that does not provide access to a database.
C.
Middleware that provides access to a database.
D.
The same thing as JDBC.
Answer: Option C
________________________________________
11. Three-tier architecture includes which of the following?
A.
Three server layers
B.
A client layer and two server layers
C.
Two client layers and one server layer
D.
Three client layers
Answer: Option B

12. Which of the following is true concerning the mainframe?
A.
It is the same thing as client/server.
B.
Requires someone to decide which code should be on the workstation or the server.
C.
Mission-critical systems have tended to remain there.
D.
All of the above.
Answer: Option C
________________________________________
13. A server cannot serve on which of the following levels?
A.
Client Layer
B.
Business Layer
C.
Database Layer
D.
All of the above.
Answer: Option A
________________________________________
14. The three different application logic components are which of the following?
A.
Presentation, Client, and Storage
B.
Presentation, Client, and Processing
C.
Presentation, Processing, and Storage
D.
Presentation, Processing, and Network
Answer: Option C
________________________________________
15. A database server is responsible for which of the following?
A.
Database storage
B.
Data processing logic
C.
Data presentation logic
D.
All of the above.
Answer: Option A
16. The DBMS that is most difficult to use is ________ .
A.
Microsoft’s SQL Server
B.
Microsoft’s Access
C.
IBM’s DB2
D.
Oracle Corporation’s Oracle
Answer: Option D

Exercise : Introduction to Database – General Questions
1. The DBMS acts as an interface between what two components of an enterprise-class database system?
A.
Database application and the database
B.
Data and the database
C.
The user and the database application
D.
Database application and SQL
Answer: Option A
________________________________________
2. Which of the following products was an early implementation of the relational model developed by E.F. Codd of IBM?
A.
IDMS
B.
DB2
C.
dBase-II
D.
R:base
Answer: Option B
________________________________________
3. The following are components of a database except ________ .
A.
user data
B.
metadata
C.
reports
D.
indexes
Answer: Option C
________________________________________
4. An application where only one user accesses the database at a given time is an example of a(n) ________ .
A.
single-user database application
B.
multiuser database application
C.
e-commerce database application
D.
data mining database application
Answer: Option A
________________________________________
5. An on-line commercial site such as Amazon.com is an example of a(n) ________ .
A.
single-user database application
B.
multiuser database application
C.
e-commerce database application
D.
data mining database application
Answer: Option C

6. Which of the following products was the first to implement true relational algebra in a PC DBMS?
A.
IDMS
B.
Oracle
C.
dBase-II
D.
R:base
Answer: Option D
________________________________________
7. SQL stands for ________ .
A.
Structured Query Language
B.
Sequential Query Language
C.
Structured Question Language
D.
Sequential Question Language
Answer: Option A
________________________________________
8. Because it contains a description of its own structure, a database is considered to be ________ .
A.
described
B.
metadata compatible
C.
self-describing
D.
an application program
Answer: Option C
________________________________________
9. The following are functions of a DBMS except ________ .
A.
creating and processing forms
B.
creating databases
C.
processing data
D.
administrating databases
Answer: Option A
________________________________________
10. Helping people keep track of things is the purpose of a(n) ________ .
A.
database
B.
table
C.
instance
D.
relationship
Answer: Option A

11. Which of the following products implemented the CODASYL DBTG model?
A.
IDMS
B.
DB2
C.
dBase-II
D.
R:base
Answer: Option A
________________________________________
12. An Enterprise Resource Planning application is an example of a(n) ________ .
A.
single-user database application
B.
multiuser database application
C.
e-commerce database application
D.
data mining database application
Answer: Option B
________________________________________
13. A DBMS that combines a DBMS and an application generator is ________ .
A.
Microsoft’s SQL Server
B.
Microsoft’s Access
C.
IBM’s DB2
D.
Oracle Corporation’s Oracle
Answer: Option B
________________________________________
14. You have run an SQL statement that asked the DBMS to display data in a table named USER_TABLES. The results include columns of data labeled “TableName,” “NumberOfColumns” and “PrimaryKey.” You are looking at ________ .
A.
user data.
B.
metadata
C.
A report
D.
indexes
Answer: Option B
________________________________________
15. Which of the following is not considered to be a basic element of an enterprise-class database system?
A.
Users
B.
Database applications
C.
DBMS
D.
COBOL programs
Answer: Option D
Exercise : The Relational Model and Normalization – General Questions
1. Every time attribute A appears, it is matched with the same value of attribute B, but not the same value of attribute C. Therefore, it is true that:
A.
A → B.
B.
A → C.
C.
A → (B,C).
D.
(B,C) → A.
Answer: Option A
________________________________________
2. The different classes of relations created by the technique for preventing modification anomalies are called:
A.
normal forms.
B.
referential integrity constraints.
C.
functional dependencies.
D.
None of the above is correct.
Answer: Option A
________________________________________
3. A relation is in this form if it is in BCNF and has no multivalued dependencies:
A.
second normal form.
B.
third normal form.
C.
fourth normal form.
D.
domain/key normal form.
Answer: Option C
________________________________________
4. Row is synonymous with the term:
A.
record.
B.
relation.
C.
column.
D.
field.
Answer: Option A
________________________________________
5. The primary key is selected from the:
A.
composite keys.
B.
determinants.
C.
candidate keys.
D.
foreign keys.
Answer: Option C

6. Which of the following is a group of one or more attributes that uniquely identifies a row?
A.
Key
B.
Determinant
C.
Tuple
D.
Relation
Answer: Option A
________________________________________
7. When the values in one or more attributes being used as a foreign key must exist in another set of one or more attributes in another table, we have created a(n):
A.
transitive dependency.
B.
insertion anomaly.
C.
referential integrity constraint.
D.
normal form.
Answer: Option C
________________________________________
8. A relation is considered a:
A.
Column.
B.
one-dimensional table.
C.
two-dimensional table.
D.
three-dimensional table.
Answer: Option C
________________________________________
9. In the relational model, relationships between relations or tables are created by using:
A.
composite keys.
B.
determinants.
C.
candidate keys.
D.
foreign keys.
Answer: Option D
________________________________________
10. A functional dependency is a relationship between or among:
A.
tables.
B.
rows.
C.
relations.
D.
attributes.
Answer: Option D
11. Table is synonymous with the term:
A.
record.
B.
relation.
C.
column.
D.
field.
Answer: Option B
Explanation:
________________________________________
12. Which of the following is not a restriction for a table to be a relation?
A.
The cells of the table must contain a single value.
B.
All of the entries in any column must be of the same kind.
C.
The columns must be ordered.
D.
No two rows in a table may be identical.
View Answer Discuss in Forum Workspace Report

________________________________________
13. For some relations, changing the data can have undesirable consequences called:
A.
referential integrity constraints.
B.
modification anomalies.
C.
normal forms.
D.
transitive dependencies.
Answer: Option B
________________________________________
14. A key:
A.
must always be composed of two or more columns.
B.
can only be one column.
C.
identifies a row.
D.
identifies a column.
Answer: Option C
________________________________________
15. An attribute is a(n):
A.
column of a table.
B.
two dimensional table.
C.
row of a table.
D.
key of a table.
Answer: Option A

11. Table is synonymous with the term:
A.
record.
B.
relation.
C.
column.
D.
field.
Answer: Option B
________________________________________
12. Which of the following is not a restriction for a table to be a relation?
A.
The cells of the table must contain a single value.
B.
All of the entries in any column must be of the same kind.
C.
The columns must be ordered.
D.
No two rows in a table may be identical.
Answer: Option C
________________________________________
13. For some relations, changing the data can have undesirable consequences called:
A.
referential integrity constraints.
B.
modification anomalies.
C.
normal forms.
D.
transitive dependencies.
Answer: Option B
________________________________________
14. A key:
A.
must always be composed of two or more columns.
B.
can only be one column.
C.
identifies a row.
D.
identifies a column.
Answer: Option C
________________________________________
15. An attribute is a(n):
A.
column of a table.
B.
two dimensional table.
C.
row of a table.
D.
key of a table.
Answer: Option A
Exercise: Object-Oriented Data Modeling – General Questions
1. The fact that the same operation may apply to two or more classes is called what?
A.
Inheritance
B.
Polymorphism
C.
Encapsulation
D.
Multiple classification
Answer: Option B
________________________________________
2. The object-oriented development life cycle is which of the following?
A.
Analysis, design, and implementation steps in the given order and using multiple iterations.
B.
Analysis, design, and implementation steps in the given order and going through the steps no more than one time.
C.
Analysis, design, and implementation steps in any order and using multiple iterations.
D.
Analysis, design, and implementation steps in any order and going through the steps no more than one time.
Answer: Option A
________________________________________
3. Multiplicity is the same as what concept for an ERD?
A.
Relationship
B.
Attribute
C.
Entity
D.
Cardinality
Answer: Option D
________________________________________
4. Composition is a stronger form of which of the following?
A.
Aggregation
B.
Encapsulation
C.
Inheritance
D.
All of the above.
Answer: Option A
________________________________________
5. An abstract class is which of the following?
A.
A class that has direct instances, but whose descendants may have direct instances.
B.
A class that has no direct instances, but whose descendants may have direct instances.
C.
A class that has direct instances, but whose descendants may not have direct instances.
D.
A class that has no direct instances, but whose descendants may not have direct instances
Answer: Option B

6. The term Complete for a UML has the same meaning as which of the following for an EER diagram?
A.
Overlapping rule
B.
Disjoint rule
C.
Total specialization rule
D.
Partial specialization rule
Answer: Option C
________________________________________
7. A UML diagram includes which of the following?
A.
Class name
B.
List of attributes
C.
List of operations
D.
All of the above.
Answer: Option D
________________________________________
8. An object can have which of the following multiplicities?
A.
Zero
B.
One
C.
More than one
D.
All of the above.
Answer: Option D
________________________________________
9. Which of the following statement is true concerning objects and/or classes?
A.
An object is an instance of a class.
B.
A class is an instance of an object.
C.
An object includes encapsulates only data.
D.
A class includes encapsulates only data.
Answer: Option A
________________________________________
10. Which of the following applies to a class rather than an object?
A.
Query
B.
Update
C.
Scope
D.
Constructor
Answer: Option C
11. The benefits of object-oriented modeling are which of the following?
A.
The ability to tackle more challenging problems
B.
Reusability of analysis, design, and programming results
C.
Improved communication between users, analysts, etc.
D.
All of the above.
Answer: Option D
________________________________________
12. The term Incomplete for a UML has the same meaning as which of the following for an EER diagram?
A.
Overlapping rule
B.
Disjoint rule
C.
Total specialization rule
D.
Partial specialization rule
Answer: Option D
________________________________________
13. A constructor operation does which of the following?
A.
Creates a new instance of a class
B.
Updates an existing instance of a class
C.
Deletes and existing instance of a class
D.
All of the above.
Answer: Option A
________________________________________
14. Which of the following is a technique for hiding the internal implementation details of an object?
A.
Encapsulation
B.
Polymorphism
C.
Inheritance
D.
All of the above.
Answer: Option A
________________________________________
15. Aggregation is which of the following?
A.
Expresses a part-of relationship and is a stronger form of an association relationship.
B.
Expresses a part-of relationship and is a weaker form of an association relationship.
C.
Expresses an is-a relationship and is a stronger form of an association relationship.
D.
Expresses an is-a relationship and is a weaker form of an association relationship.
Answer: Option A

Man Begs Neighbour to Allow His Son Have sex With Her Daughter to Test if Penis is Working

 

A man allegedly pleaded with his female neighbour to allow his teen son have sex with her teen daughter so they could find out if his penis is still working fine.

It all started when the son raised alarm that a middle-aged man identified as Taoheeb had touched him in a suspicious manner as he walked along the road in Idimu and this caused his penis to shrink. It was also claimed that it made him unable to have an erection. This caused serious commotion and the suspect was attacked.

Police intervened in time to rescue him and take him to the Area M Command, Idimu, Lagos

At the Police Command, the suspect denied tampering with the victim’s penis and said he was ready to accept whatever punishment was given to him if it was discovered that indeed he tampered with the boy’s penis.

P.M. Express reports that someone suggested that the boy should go and test his manhood with a sex worker, but his parents objected, saying it was against their religious belief and he was too young for sex workers. The father then called the female neighbour aside and begged her to allow his son test the efficacy of his penis on her teen daughter.

The neighbour then asked the man what will happen if his son impregnates her daughter in the course of testing, considering he’s not old enough to get married. The boy’s father was unable to answer and this amused spectators.

The father eventually took his son home and when the boy’s parents did not return to the station, police released the suspect.

Sultan Blasts Northern Governors, Says ‘You Are Lazy’

The Sultan of Sokoto, Alhaji Saad Abubakar, on Thursday blasted some Nothern governors for what he described as lazy attitude to governance.

The Sultan stated this at a joint meeting of the Northern Governors’ Forum and traditional rulers at Sir Kashim Ibrahim House in Kaduna.

sultanSa'd.jpg

The sultan said the governors must show practical commitment to discharging their duties by avoiding procrastination and implementing decisions capable of turning around the poor situation of the north.

He said: “it is an indication that the northern establishment is set for self-evaluation. It is no longer prepared to pamper the issue of poor development in the north as the sultan’s call on the region’s political leadership to brace to the challenges of development is unmistakeable’.