The Impacts of Drinking Alcohol, Using Marijuana, and Smoking Cigarettes as a Teenager on the Educational Attainment and the Income of Young Adults

It is widely believed that activities such as drinking alcohol, smoking cigarettes, and using marijuana during the teenage years have a harmful effect on a youth\u27s development, thus damaging his or her value in the labor market once the individual reaches adulthood. There have been several studies in the past that have looked into the consequences of partaking in such activities during both the adult and college years, but this paper will investigate how the use of alcohol, marijuana, and cigarettes at the age of 16 affects the average individual\u27s future income and the amount of education completed by the time he or she becomes a young adult. Using data from the National Longitudinal Survey of Youth 1997 (NLSY97), this paper will examine not only how having tried each of the aforementioned substances affects one\u27s future outlook, but also the effect that various levels of drug or alcohol use at the age of 16 has on both the number of grades completed and the amount of money earned in the past year when the individual hits the ages of 23 and 25. Through regression analysis, the study finds that the net effect of using alcohol as a teenager on income as a young adult is generally positive for the sample. However, alcohol use as a teenager tended to have a negative effect on the amount of schooling finished. Both marijuana and cigarette use as a teen are met with a decrease in earnings and a reduction in the amount of education completed

Dynamic equations for three different qudits in a magnetic field

A closed system of equations for the local Bloch vectors and spin correlation functions of three magnetic qudits, which are in an arbitrary, time-dependent, external magnetic field, is obtained using decomplexification of the Liouville-von Neumann equation. The algorithm of the derivation of the dynamic equations is presented. In the basis convenient for the important physical applications structure constants of algebra su(2S+1) are calculated.Comment: 11 page

The absoption refrigerator as a thermal transformer

The absorption refrigerator can be considered a thermal transformer, i.e. a device that is analogous to the electric transformer. The analogy is based on a correspondence between the extensive quantities entropy and electric charge and that of the intensive variables temperature and electric potential

Efficiency at maximum power output of an irreversible Carnot-like cycle with internally dissipative friction

We investigate the efficiency at maximum power of an irreversible Carnot engine performing finite-time cycles between two reservoirs at temperatures $T_h$ and $T_c$ $(T_c<T_h)$, taking into account of internally dissipative friction in two "adiabatic" processes. In the frictionless case, the efficiencies at maximum power output are retrieved to be situated between $\eta_{_C}/$ and $\eta_{_C}/(2-\eta_{_C})$, with $\eta_{_C}=1-T_c/{T_h}$ being the Carnot efficiency. The strong limits of the dissipations in the hot and cold isothermal processes lead to the result that the efficiency at maximum power output approaches the values of $\eta_{_C}/$ and $\eta_{_C}/(2-\eta_{_C})$, respectively. When dissipations of two isothermal and two adiabatic processes are symmetric, respectively, the efficiency at maximum power output is founded to be bounded between 0 and the Curzon-Ahlborn (CA) efficiency $1-\sqrt{1-\eta{_C}}$, and the the CA efficiency is achieved in the absence of internally dissipative friction

Enrichissement de la croissance en emploi et productivité

Le ralentissement des gains de productivité par tête observé depuis la fin des années 80 en Europe, et notamment en France, est susceptible de plusieurs types d'interprétations. Il pourrait refléter un tassement des gains de la productivité globale des facteurs, une substitution des têtes aux heures ou un rééquilibrage des productivités apparentes des différents facteurs de production. L'objet de cet article est de souligner le rôle de ce mouvement de rééquilibrage, en réponse à une baisse du coût relatif du travail, notamment peu qualifié. Dans cette perspective, la baisse des gains de productivité par tête, loin d'être défavorable, refléterait un enrichissement de la croissance en emploi dans un contexte de décrue du chômage structurel. Nous illustrons les mécanismes sous-jacents en nous appuyant sur un modèle d'offre et de demande de travail à deux qualifications. La version dynamique du modèle est calibrée afin de donner une image des évolutions temporelles de la production, de l'emploi, ainsi que des productivités apparentes des facteurs en réponse à des chocs de coûts.Emploi, croissance, productivité

Intrinsic Periodicity of Time and Non-maximal Entropy of Universe

The universe is certainly not yet in total thermodynamical equilibrium,so clearly some law telling about special initial conditions is needed. A universe or a system imposed to behave periodically gets thereby required ``initial conditions". Those initial conditions will \underline{not} look like having already suffered the heat death, i.e. obtained the maximal entropy, like a random state. The intrinsic periodicity explains successfully why entropy is not maximal, but fails phenomenologically by leading to a \underline{constant}entropy.Comment: 8 page

Thermodynamic Bounds on Efficiency for Systems with Broken Time-reversal Symmetry

We show that for systems with broken time-reversal symmetry the maximum efficiency and the efficiency at maximum power are both determined by two parameters: a "figure of merit" and an asymmetry parameter. In contrast to the time-symmetric case, the figure of merit is bounded from above; nevertheless the Carnot efficiency can be reached at lower and lower values of the figure of merit and far from the so-called strong coupling condition as the asymmetry parameter increases. Moreover, the Curzon-Ahlborn limit for efficiency at maximum power can be overcome within linear response. Finally, always within linear response, it is allowed to have simultaneously Carnot efficiency and non-zero power.Comment: Final version, 4 pages, 3 figure

Driven Spin Systems as Quantum Thermodynamic Machines: Fundamental Limits

We show that coupled two level systems like qubits studied in quantum information can be used as a thermodynamic machine. At least three qubits or spins are necessary and arranged in a chain. The system is interfaced between two split baths and the working spin in the middle is externally driven. The machine performs Carnot-type cycles and is able to work as heat pump or engine depending on the temperature difference of the baths $\Delta T$ and the energy differences in the spin system $\Delta E$. It can be shown that the efficiency is a function of $\Delta T$ and $\Delta E$.Comment: 9 pages, 11 figures, accepted for publication in Phys. Rev.

Quantum mechanical Carnot engine

A cyclic thermodynamic heat engine runs most efficiently if it is reversible. Carnot constructed such a reversible heat engine by combining adiabatic and isothermal processes for a system containing an ideal gas. Here, we present an example of a cyclic engine based on a single quantum-mechanical particle confined to a potential well. The efficiency of this engine is shown to equal the Carnot efficiency because quantum dynamics is reversible. The quantum heat engine has a cycle consisting of adiabatic and isothermal quantum processes that are close analogues of the corresponding classical processes.Comment: 10 page