Notes, summaries, assignments, exams, and problems for Baccalaureate

The Crucial Role of English Proficiency Today

In past years, many people could build a career with only basic English knowledge. However, things have changed, and now a high level of English is often required for any career or job. For example, in Spain, to pursue a career, one must pass a selectividad exam, and English is one of the required subjects. Therefore, if you don't speak English, it will be very difficult to establish a career.

Also, in Spain, students can obtain Becas Erasmus (Erasmus scholarships) to travel to another country and study their chosen field for a year. Knowing English also allows you to study or work in English-speaking countries like England, which is a very interesting country. Furthermore, having a career path may... Continue reading "Essential Skills for Today: Language Proficiency and Technology Use" »

Gerineldo Analysis and Princess Part

Acid Value Determination in Oils: Principle and Procedure

Here's an explanation of the principle and procedure involved in determining the acid value of an oil sample:

Principle

The acid value of an oil sample is a measure of the amount of free fatty acids present in the oil. The principle of the acid value determination is based on the reaction between the free fatty acids in the oil and a strong base, such as potassium hydroxide (KOH). The reaction is as follows:

RCOOH (Free Fatty Acid) + KOH → RCOOK (Potassium Salt) + H₂O

Procedure

Here's the step-by-step procedure for determining the acid value of an oil sample:

1. Apparatus

• 250 mL Erlenmeyer flask
• Burette
• Pipette
• Volumetric flask
• Phenolphthalein indicator

2. Reagents

• Potassium hydroxide (KOH) solution

1. Anagram Detection: C++ String Comparison

This C++ program determines if two input strings are anagrams of each other. It achieves this by converting both strings to lowercase, sorting their characters alphabetically, and then comparing the sorted strings. If they are identical, the original strings are considered anagrams.

#include<bits/stdc++.h>
using namespace std;

int main(){
    string s2,s1;
    cin>>s1>>s2;
    transform(s1.begin(),s1.end(),s1.begin(),::tolower);
    transform(s2.begin(),s2.end(),s2.begin(),::tolower);
    sort(s1.begin(),s1.end());
    sort(s2.begin(),s2.end());
    cout<< (s2==s1);
}

2. Array Subarray: C++ Sliding Window Minimum

This C++ program attempts to find the maximum of minimums within... Continue reading "C++ & C Programming Solutions: Algorithms & Patterns" »

Complete the sentences with the verbs below in Past Simple:

walk, enjoy, like, watch, travel, finish, listen

1. Lucy liked her birthday presents.
2. Last weekend I walked in the mountains for 2 hours.
3. We enjoyed the party very much.
4. Ken listened to his favorite CD yesterday.
5. My sister studied Maths for an exam.
6. They traveled to the USA in 2003.
7. Dad washed his car last weekend.
8. The film finished at 11:30.

Write the sentences in negative:

1. Lucy didn't like her birthday presents.
2. Last weekend I didn't walk in the mountains for 2 hours.
3. We didn't enjoy the party very much.
4. Ken didn't listen to his favorite CD yesterday.
5. My sister didn't study months for German.
6. They didn't travel to the USA in 2003.
7. Dad didn't wash his car last weekend.
8. The film didn't finish at 11:30.

Plasmids pBR322 and pUC18/19

pBR322

pBR322, developed in 1977, is a foundational plasmid in molecular biology. Key features include:

• Size: ~4,361 base pairs (bp)
• Origin of Replication: Allows independent replication within bacteria.
• Selection Markers:
  • ampR: Confers ampicillin resistance.
  • tetR: Confers tetracycline resistance.
• Cloning Sites: Multiple sites for inserting foreign DNA.
• Applications: Gene cloning, expression, and manipulation.

pUC18/19

pUC18/19, derived from pBR322 in the early 1980s, simplifies cloning. Key features include:

• Size: ~2,686 bp
• Origin of Replication: High-copy-number pMB1 ori for increased yield.
• Selection Marker:
  • lacZ: Beta-galactosidase gene; enables blue/white screening for insert identification.
• Cloning Sites: Multiple cloning

Tmux Commands Reference

Introduction to Tmux

Tmux (Terminal Multiplexer) is a powerful terminal multiplexer for Unix-like operating systems. It allows you to manage multiple terminal sessions from a single window, enhancing your command-line productivity.

Basic Tmux Commands

$ tmux

$ tmux new -s myname

$ tmux ls

$ tmux a

$ tmux a -t myname

$ tmux kill-ses -t myname

$ tmux kill-ses -a

$ tmux kill-ses -a -t myname

$ tmux source-file ~/.tmux.conf

$ tmux show-options -g

$

Longest Substring Without Repeating Characters

This problem involves finding the length of the longest substring in a given string that does not contain any repeating characters. A common approach uses a sliding window technique with a Set to efficiently track unique characters.

Strategy:

• Utilize a Set to store characters within the current window.
• Iterate through the string with a right pointer, adding characters to the Set.
• If a duplicate character is encountered, move the left pointer forward, removing characters from the Set, until the duplicate is no longer present.
• At each step, update the maximum length found.

Java Implementation Snippet

class Solution {
    public int findLongestSubstringWithoutRepeatingCharacter(String str) {
        Set&